Oral care article comprising a hydrophobic delivery carrier and solid hydrophilic particle comprising a bleaching agent

ABSTRACT

An oral care article in form of a strip for use in the oral cavity. The oral care article includes a hydrophobic delivery carrier comprising embedded solid hydrophilic particles comprising at least one bleaching agent, wherein at least about 20 parts by weight of the particles dissolve in about 100 parts by weight of water and/or the particles increase in volume and/or weight by at least about 50% upon contact with water.

FIELD OF THE INVENTION

The present invention relates to oral care articles comprising ahydrophobic delivery carrier and solid hydrophilic particles comprisinga bleaching agent suitable for use in the oral cavity.

BACKGROUND OF THE INVENTION

Currently in the marketplace are dental products by which variouscosmetic and/or therapeutic actives are delivered to teeth and the oralcavity. Examples of such products include brushing aids, such asdentifrice products for delivery of oral care actives for examplepolyphosphates or fluorides; mouthwashes containing breath fresheners orantibacterial actives; and whitening strips for the delivery ofbleaching actives to the teeth. The use of a dental strip has beenrecognized as a convenient and inexpensive way to deliver cosmetic andtherapeutic benefits to the teeth and mucosal surfaces of the oralcavity; for example, dental whitening strips, where a whiteningcomposition is applied to a strip and thereafter applied to the teeth toachieve sustained contact between the teeth and the whitening article.

Despite the above known approaches for the treatment or improvement oforal conditions, especially for the whitening of teeth, a need stillexists for providing products with improved performance, e.g. increasedspeed of whitening, improved bleaching efficacy, higher anti-bacterialeffects, decreased tooth-sensitivity, and/or decreased oral soft tissueirritation. Previous attempts to address these issues include increasingthe level of the bleaching agent in the articles. This approach,however, can present problems. The user may experience increasedirritation and/or sensitivity which may be associated with using anincreased amount of a bleaching agent. Therefore, despite the aboveknown approaches for the treatment of oral conditions, especially forthe whitening of teeth, a need still exists for providing products withimproved bleaching efficacy, increased speed of whitening, decreasedtooth-sensitivity, and/or decreased oral soft tissue irritation.

SUMMARY OF THE INVENTION

The present invention provides an oral care article comprising:

-   -   a) a solid hydrophobic delivery carrier in form of a strip        having a length and a width forming a first surface and having a        thickness extending from the first surface to a second surface,        wherein the average thickness is less than 3 mm;    -   b) solid hydrophilic particles comprising at least one bleaching        agent, wherein the solid hydrophilic particles release the        bleaching agent upon contact with water; and wherein the solid        hydrophilic particles are disposed in and are embedded in the        solid hydrophobic delivery carrier, wherein the solid        hydrophilic particles are disposed i) at least partially below        the first surface, and ii) at least partially at or above the        first surface of the solid hydrophobic delivery carrier; and        wherein at least about 20 parts by weight of the particles        dissolve in about 100 parts by weight of water and/or the        particles increase in volume and/or weight by at least about 50%        upon contact with water.

The solid hydrophobic delivery carrier may comprise a material having acone penetration consistency value of less than about 10 as measured byASTM D937-07.

The present article may be used to deliver health, therapeutic orcosmetic benefits to the oral cavity by directly applying the bleachingagent to the teeth and/or the oral cavity. In one aspect, the article ofthe present invention can be used for reducing and/or removing caries,plaque, tartar and stain, promoting gum health, preventing and treatingcavities, improving breath, promoting bleaching, providing antibacterialeffects and/or a combination thereof.

The article may be provided as a kit, for example together with anapparatus for increasing the efficacy of the bleaching agent(s), such asan electromagnetic radiation source.

The present invention is further directed to cosmetic and/ornon-therapeutic method for whitening teeth using the article or the kitas disclosed herein comprising:

-   -   a) applying the article to at least one tooth surface such that        the first surface of the hydrophobic delivery carrier contacts        the at least one tooth surface;    -   b) letting the article stay on the at least one tooth surface        for a suitable period of time such as at least 1 minute; and    -   c) optionally applying electromagnetic radiation for a suitable        period of time, such as at least 1 minute.

The article may be further provided together with instructions to usethe article.

The article is directly attached to the teeth or the oral cavity, i.e.the adhesion function or attachment mechanism can be provided directlyby the article, e.g. the hydrophobic delivery carrier itself. Forexample, the article may optionally be of sufficient size that onceapplied the article overlaps with the oral soft tissues rendering moreof the teeth surface available for the effect achieved with thebleaching agent(s). The article may be attached to the oral cavity byphysical interference or mechanical inter-locking between the articleand the oral surfaces including the teeth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an article 10 in strip form havingrounded corners comprising solid hydrophilic particles 20 which may bein contact with the environment or which may show a greater number ofparticles 20 at a first surface 14 (FIG. 1B);

FIG. 2A is a cross-sectional view, taken along section line 2-2 of thearticle 10 of FIG. 1A and FIG. 2B is a cross-sectional view, taken alongsection line 2-2 of the article 10 of FIG. 1B;

FIG. 3 is a cross-sectional plan view, showing the article 10 attachedto the teeth 22;

FIG. 4 is a cross-sectional elevation view of a tooth, taken alongsection line 4-4 of FIG. 3 , showing the article 10 adhesively attachedto the teeth 22;

FIG. 5A is a photograph image of an article 10 in strip form beingformed into a dental tray (FIG. 5B) comprising a notch 18 (FIG. 5C);

FIG. 6 is a photograph image of a sheet of wax usable as hydrophobicdelivery carrier 12 comprising embedded solid hydrophilic particles 20(Example IV-A);

FIG. 7 is a microscope image of a sheet of wax usable as hydrophobicdelivery carrier 12 comprising embedded solid hydrophilic particles 20(Example IV-A);

FIG. 8A and FIG. 8B are microscope images of a sheet of wax usable ashydrophobic delivery carrier 12 combined with embedded solid hydrophilicparticles 20 (Example V-A); FIG. 8A is an image of a first surface 14,and FIG. 8B is an image of a second surface 16.

FIG. 9 shows a device for delivering electromagnetic radiation towardthe tooth surface.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that bleaching agent(s) can be effective at very lowconcentrations by weight of an oral care article, if they are providedas solid hydrophilic particles and combined with a hydrophobic deliverycarrier to form an oral care article as disclosed herein. The oral carearticle of the present invention can comprise, from about 0.01% to about50%, or from about 0.1% to about 30%, or from about 0.1% to about 25%,or from about 0.1% to about 15%, or from about 0.3% to about 10%, byweight of the article, of solid hydrophilic particles comprising ableaching agent; wherein the solid hydrophilic particles are soluble inwater, swell upon contact with water, and release the bleaching agentupon contact with water or water comprising liquids.

The solid hydrophilic particles are disposed on and in by being embeddedin, the hydrophobic delivery carrier to form the oral care article ofthe present invention. The solid hydrophilic particles comprise thebleaching agent(s), wherein the concentration of the bleaching agent ata first surface of the hydrophobic delivery carrier may be greater thanthe concentration of the bleaching agent at a second surface. Examplesfor the at least one bleaching agent(s) comprise a source of peroxideradicals, metal chlorites, perborates, percarbonates, peroxyacids,persulfates, compounds that form the preceding compounds in situ, andcombinations thereof, wherein complexes of hydrogen peroxide andpolyvinylpyrrolidone (PVP) polymers (also known as Peroxydone) and/orurea peroxide are preferred. Without wishing to be bound by theory, itis believed that when the article contacts the surface of a tooth withthe first surface, the solid hydrophilic particles that are embedded inthe hydrophobic delivery carrier deliver the bleaching agent to thehydrophilic biofilm on the surface of the tooth. This can lead toincreased bleaching efficacy with lower total levels of bleachingagents.

The term “delivery carrier” as used herein comprises a material in theform of a strip that is used to deliver bleaching agents from solidhydrophilic particles to a surface, for example a tooth surface. Adelivery carrier as used herein may be flat or pre-formed in athree-dimensional shape, for example in the shape of a dental arch. Thematerial of the “delivery carrier” should be compatible with the oralcavity and comfortable for the user and is hydrophobic. Examplematerials for a hydrophobic delivery carrier include wax(es), polymer(s)and combinations thereof.

The terms “hydrophobic and “hydrophilic” are used herein according tocommon general knowledge. The term “hydrophilic” is used for object(s),article(s), molecule(s), compound(s), entity(s) that are attracted towater and other polar materials. The term “hydrophobic” is usedaccordingly for object(s), article(s), molecule(s), compound(s),entity(s) that are not attracted to and/or repelled by water and otherpolar materials.

The term “strip” as used herein comprises a material 1) whose longestdimension length is generally greater than its width, and 2) whose widthis generally greater than its thickness. Strips may be rectangular,arched, curved, semi-circular, have rounded corners to avoid irritationof the soft tissue of the oral cavity. “Rounded corners,” as used hereinmeans generally lacking sharp angles or points, for example one or moreangles of 135° or less. In addition, a strip may be bent or shaped intothree dimensional shapes, for example into a dental arch, orcombinations thereof. Strips may be solid, textured, rigid, moldable,deformable, permanently deformable, or combinations thereof. Stripsuseful in the present invention may be suitably shaped to fit into anoral cavity.

The term “oral care article” as used herein refers to an article ofmanufacture for use in the oral cavity, for example for use on teeth inthe oral cavity. The oral care article may comprise a solid hydrophobicdelivery carrier combined with solid hydrophilic particles comprising atleast one bleaching agent.

The term “unit-dose article” as used herein means an article that isused once and disposed of subsequently.

The term “removable article” as used herein means an article that isremoved from the oral cavity after use.

The term “stick type product” as used herein refers to an article whichis a bar of an apparently firm solid material held within a dispensingcontainer which when applied to a surface to be treated, retains itsstructural integrity and shape. When a portion of the stick is drawnacross a surface, a film of the stick article is transferred to thesurface. Examples include lip balm and lipstick. A stick type product isgenerally used several times and thus, cannot be considered as aunit-dose article as used herein. In addition, when a portion of thestick type product is drawn across a surface a film of the stickcomposition is transferred to the surface which is generally not removedand/or removable from the oral cavity after use.

The term “moldable” as used herein means that the material thehydrophobic delivery carrier and/or the article conforms to the generalshape of a dental arch when applied by the user. Examples of hydrophobicdelivery carriers that are “moldable” include a casting wax clear sheet24 gauge (reference number 114009 supplied by Freeman ManufacturingCompany, Ohio, USA) cut into a strip about 0.51 mm thick, about 22 mmwide and about 62 mm long.

The term “wax” as used herein means organic compounds that arehydrophobic and solid at room temperature, for example higher alkanes.Waxes can have a drop melting point as measured by ASTM method D127-08from about 60° C. to about 120° C., or from about 70° C. to about 110°C., or from about 80° C. to about 100° C., or from about 90° C. to about100° C., and/or a needle penetration consistency value as measured byASTM method D1321-16a from about 0.1 to about 100, or from about 0.5 toabout 50, or from about 1 to about 10, and/or a cone penetrationconsistency value as measured by ASTM method D937-07 less than 10, orfrom about 1 to 9, or less than about 5.

The term “needle penetration consistency value” as used herein means thedepth, in tenths of a millimeter, that a standard needle will penetratethe sample under fixed conditions of mass, time, and temperature. Theneedle penetration consistency value is measured according to ASTMmethod D1321-16a.

The term “cone penetration consistency value” as used herein means thedepth, in tenths of a millimeter, that a standard cone will penetratethe sample under fixed conditions of mass, time, and temperature. Thecone penetration consistency value is measured according to ASTM methodD937-07.

The term “particle” as used herein is a discrete, solid material. Solidparticles have dimensions larger than individual atoms or molecules andare typically sub-micron to about five millimeters in their largestdimension. Particles may be agglomerated into an agglomerate of discreteparticles.

The term “solid hydrophilic particle” as used herein is a solid particlethat is soluble in water and/or swells (increases in volume and/orweight) upon contact with water, and releases bleaching agent uponcontact with water. In addition, the solid hydrophilic particle isinsoluble in the hydrophobic delivery carrier. The solid hydrophilicparticle comprises a bleaching agent which is released from the solidhydrophilic particle upon contact with water. If a bleaching agent isreleased, the bleaching agent may be a gas, liquid, or solid dissolvedin a liquid. The solid hydrophilic particles may further compriseingredients that are water soluble, water miscible, or combinationsthereof, such as for example: water, water-soluble solvents, alcohols,carbopol, polyalkylene glycols, humectants, glycerin, sorbitol, xylitol,butylene glycol, polyethylene glycol, and propylene glycol, and mixturesthereof. If these ingredients are added to or are present in the solidhydrophilic particles, the percentage of the solid hydrophilic particlesin the article is calculated by excluding these ingredients. Ifwater-insoluble or water-immiscible fillers are added to the solidhydrophilic particles, the percentage of the solid hydrophilic particlesin the article is calculated by excluding these fillers.

The term “immiscible” or “insoluble” as used herein means less than 1part by weight of the substance dissolves in 100 parts by weight of asecond substance.

The term “solubility” as used herein is the maximum number of parts byweight of the substance that can dissolve in 100 parts by weight of asecond substance.

The term “embedded” or “embedded particle” as used herein means thatsaid solid particle is disposed i) at least partially below a surface,and ii) at least partially at or above the said surface of a solidhydrophobic delivery carrier. Examples of embedded particles includesolid hydrophilic particles pressed into a surface of a wax sheet, e.g.a casting wax clear sheet 24 gauge (reference number 114009 supplied byFreeman Manufacturing Company, Ohio, USA) at for example 625 PSI for 60seconds.

The term “bleaching agent” as used herein is a component present in thesolid hydrophilic particle that provides a bleaching and/or whiteningbenefit. For example, if urea peroxide (also known as urea hydrogenperoxide adduct) is used as a solid hydrophilic particle, the hydrogenperoxide component of the urea peroxide is a bleaching agent. Similarly,if a complex of hydrogen peroxide and polyvinylpyrrolidone (PVP) polymeris used as a solid hydrophilic particle, the hydrogen peroxide componentof the complex of hydrogen peroxide and polyvinylpyrrolidone (PVP)polymer is a bleaching agent.

By “safe and effective amount” as used herein means an amount of acomponent, high enough to significantly (positively) modify thecondition to be treated or to affect the desired results, but low enoughto avoid serious side effects (at a reasonable benefit/risk ratio),within the scope of sound medical/dental judgment. The safe andeffective amount of a component will vary with the specific conditionbeing treated, the age and physical condition of the patient beingtreated, the severity of the condition, the duration of treatment, thenature of concurrent therapy, the specific form employed, and thespecific vehicle from which the component is applied.

By “a sufficient period of time to achieve the desired effect of thebleaching agent” as used herein is meant that the article comprising thebleaching agent may be used or worn by the participant or theparticipant may be instructed to use or wear the article comprising thebleaching agent from about 10 seconds to about 24 hours, or from about 1minute to about 2 hours, or from about 5 minutes to about 1 hour perapplication. The treatments may be applied from about 1 time a day toabout 10 times a day, or from about 1 time a day to about 5 times a day,or from about 1 time a day to about 3 times a day. The treatments may beapplied for from about 1 day to about 8 weeks, or from about 1 day toabout 4 weeks, or from about 1 day to about 1 week. Further, the lengthof treatment to achieve the desired benefit, for example, toothbleaching, may last for a specified period of time, which may berepeated if necessary, for example from about one day to about sixmonths or ongoing. The optimal duration and frequency of applicationwill depend on the desired effect, the severity of any condition beingtreated, the health and age of the user and like considerations.

The term “equivalent diameter” of a particle as used herein means thediameter of a sphere having the same volume as the particle.

All percentages and ratios used herein are by weight of the article (wt%), unless otherwise indicated. All percentages, ratios, and levels ofingredients referred to herein are based on the actual amount of theingredient, and do not comprise solvents, fillers, or other materialswith which the ingredient may be combined as a commercially availableproduct, unless otherwise indicated.

All measurements referred to herein are made at about 23° C. (i.e. roomtemperature) unless otherwise specified.

“Active and other ingredients” useful herein may be categorized ordescribed herein by their cosmetic and/or therapeutic benefit or theirpostulated mode of action or function. However, it is to be understoodthat the active and other ingredients useful herein can, in someinstances, provide more than one cosmetic and/or therapeutic benefit orfunction or operate via more than one mode of action. Therefore,classifications herein are made for the sake of convenience and are notintended to limit an ingredient to the specifically stated function(s)or activities listed.

The term “orally acceptable” comprises one or more compatible solid orliquid excipients or diluents which are suitable for use in the oralcavity. By “compatible,” as used herein, is meant that the componentsare capable of being commingled without interaction in a manner whichwould substantially reduce the article's stability and/or efficacy.

Oral Care Articles

The oral care articles as disclosed herein comprise a solid hydrophobicdelivery carrier combined with solid hydrophilic particles comprising atleast one bleaching agent. The solid hydrophilic particles are disposedin and embedded in the solid hydrophobic delivery carrier. Theconcentration of the bleaching agent at a first surface of thehydrophobic delivery carrier may be greater than the concentration ofthe bleaching agent at a second surface of the hydrophobic deliverycarrier, as the solid hydrophilic particles are embedded in thehydrophobic delivery carrier. The components and properties of the solidhydrophilic particles as well as of the hydrophobic delivery carrier arechosen to allow for an optimal release of the bleaching agent readilyfrom the article.

The present invention is directed to oral care articles comprising atotal overall concentration of bleaching agent at very low levels, suchas less than 0.1%, by weight of the article. It is found that even atsuch low levels of bleaching agent, the article may still deliver arelatively high level of treatment efficacy.

The articles as disclosed herein comprise a solid hydrophobic or solidwater-insoluble delivery carrier with embedded solid hydrophilicparticles comprising at least one bleaching agent, wherein theconcentration of the bleaching agent at a first surface of thehydrophobic delivery carrier may be greater than the concentration ofthe bleaching agent at a second surface of the hydrophobic deliverycarrier.

The articles as disclosed herein may comprise a solid thermoplastichydrophobic delivery carrier combined with solid hydrophilic particlescomprising at least one bleaching agent, wherein the solid hydrophilicparticles are embedded in the hydrophobic delivery carrier and theconcentration of the bleaching agent at a first surface of thehydrophobic delivery carrier or article is greater than theconcentration of the bleaching agent at a second surface of thehydrophobic delivery carrier or article.

Without wishing to be bound by theory it is believed that when thepresent article is brought into contact with a tooth surface, the solidhydrophilic particles deliver the bleaching agent to the hydrophilicbiofilm of the surface. The possible net effect is that the teethtreating effect is started only after contact with the tooth surface tobe treated. That means, the hydrophilic bleaching agent may be protectedagainst environmental influence and thereby stabilized by thehydrophobic delivery carrier of the article until use as well as duringuse. Thereby, the bleaching effect may be applied to the tooth surfaceand the hydrophilic bleaching agent may be potentially shielded againstthe oral environment during use. Thereby the efficacy of the bleachingagent may be enhanced and/or accelerated.

Without wishing to be bound by theory, the present invention may improvethe delivery of the hydrophilic bleaching agent to an oral cavitysurface, such as a tooth or a gum surface, due to the partialhydrophobic and partial hydrophilic nature of the article. Due to thedriving force resulting therefrom, the bleaching agent may be driventowards the tooth surface. Thereby increased speed and/or increasedefficacy of the bleaching agent may be achieved, even thoughsurprisingly low total levels of the bleaching agent are used. Thepresent invention, therefore, at a given total overall concentration,such as about 0.1% by weight or below of a bleaching agent, may delivera surprisingly high level of treatment efficacy, and thus may requirefewer applications to get the same degree of efficacy compared toapplication of the prior art, or may require a lower concentration toget the same degree of efficacy. Without wishing to be bound by theory,it is believed that part of the reason for the high efficacy deliveredby the articles of the present invention may be because they may beattached to the oral cavity by physical interference or mechanicalinter-locking between the hydrophobic delivery carrier and the oralsurfaces including the teeth, or are self-adhesive or self-substantiveto teeth, and resistant to being washed away in saliva or other liquids.This may keep the bleaching agents in contact with the oral surface suchas the tooth surface or in the oral cavity for a long time, thus leadingto high efficacy. It is worth noting that in general substances that areadhesive or substantive to the oral cavity are hydrophilic becausesurfaces in the oral cavity are wet. It is also worth noting that someproduct forms, especially stick type products, may need an addedsubstantivity agent to adhere the article to surfaces in the oralcavity. However, it has been found that the article of the presentinvention and/or the hydrophobic delivery carrier of the presentinvention may be attached to the oral cavity by physical interference ormechanical inter-locking between the hydrophobic delivery carrier andthe oral surfaces including the teeth, or are self-adhesive orself-substantive to surfaces in the oral cavity such as tooth surfaceseven without an added adhesive (for example hydrophilic particles thatbecome sticky when activated by moisture, or hydrophilic liquids) oradded substantivity agent. Achieving adhesiveness or substantivitywithout the use of an added hydrophilic adhesive or hydrophilicsubstantivity agent is especially useful because it may help make thearticle resistant to being washed away in saliva or other liquids—thusleading to higher efficacy. This is because achieving adhesiveness orsubstantivity without the use of an added hydrophilic adhesive or addedhydrophilic substantivity agent can allow us to increase the level ofhydrophobic components (that resist being washed away) and/or decreasethe level of hydrophilic components (that are susceptible to beingwashed away). Counterintuitively, this can help increase thesubstantivity of the article leading to a high concentration of thebleaching agent in contact with the oral surface such as the toothsurface or in the oral cavity for a long time, this in turn leading tohigh efficacy. Thus, the articles of the present invention and/or thehydrophobic delivery carrier of the present invention may besubstantially free of an added adhesive, or substantially free of anadded hydrophilic adhesive (for example hydrophilic particles thatbecome sticky when activated by moisture) or an added hydrophilicsubstantivity agent, or substantially free of an added hydrophilicliquid adhesive (for example glycerin). In one aspect, the article ofthe present invention and/or the hydrophobic delivery carrier of thepresent invention may be attached to the oral cavity by physicalinterference or mechanical inter-locking between the hydrophobicdelivery carrier and the oral surfaces including the teeth or areself-adhesive or self-substantive to the oral cavity such as the toothsurface.

It is also worth noting that some product forms, especially stick typeproducts, may need an added active releasing agent or added peroxidereleasing agent to improve the release of the bleaching agent orperoxide trapped in the stick type product. In general, active releasingagents or peroxide releasing agents are hydrophilic water-soluble orwater-swellable polymers or hydrophilic liquids that may providehydration channels in the article allowing water to penetrate thearticle and allowing the bleaching agent or peroxide to leach out. Anadded peroxide releasing agent (such as sodium percarbonate) may helpbreak the hydrophobic matrix as a result of micro bubbles that may begenerated when it comes in contact with water; and this disruption mayenhance the release of the whitening or bleaching agents, such as thehydrogen peroxide. However, the articles of the present invention areself-releasing (for example, they release bleaching agents or peroxideeven without an added active releasing agent or an added peroxidereleasing agent).

The retention of the article on the tooth surfaces may be improved asthe hydrophobic delivery carrier resists salivary dilution and salivaryenzymes which can decompose the bleaching agent, such as peroxide. Evenfurthermore, the hydrophobic delivery carrier does not dehydrate theteeth creating an outward flux of water created by many hydrophilicarticles containing hydrophilic adhesives such as polycarboxylic acid.Since the hydrophobic delivery carrier does not dehydrate the teeth itmay result in a surprisingly low level of tooth sensitivity even whiledelivering a surprisingly high level of bleaching efficacy.

The hydrophobic delivery carrier may provide further advantages. Forexample, the hydrophobic delivery carrier may represent a stable matrixfor ingredients which are soluble in the hydrophobic delivery carrier.For example, many flavor ingredients usually used in oral care articlesare soluble in the hydrophobic delivery carrier. That means the flavoringredients may be protected from any influence of the hydrophilicbleaching agent, in the oral care article. During use of the article atthe tooth surface at least part of the hydrophobic delivery carrier maybe located towards the soft oral tissues, such as the mucosa, therebypresenting the ingredients which are present in the hydrophobic deliverycarrier, such as flavor compounds, to the oral cavity. For example,flavor ingredients may be located at the second surface of thehydrophobic delivery carrier so that the solid hydrophilic particles andan optional flavor ingredient are located at opposite sides of thehydrophobic delivery carrier and can be released independently to theoral cavity. The hydrophobic delivery carrier may shield the bleachingagent against any influence from the oral cavity, such as dilution bysaliva. The shielding effect may also apply to the tooth surface(s)themselves, wherein the hydrophobic delivery carrier may provide greaterhydration of the teeth surfaces.

It is worth noting that stick type products may be unhygienic forrepeated use inside the oral cavity due to potential contamination orbio-film build-up. Saliva or moisture may penetrate the stick typeproduct when used inside the oral cavity and this may degrade thebleaching agents such as peroxides during storage between uses; and thisdegradation may be further accelerated by enzymes present in saliva.Furthermore, this degradation could be most pronounced at the tip of thestick type product that comes in direct contact with the saliva ormoisture inside the oral cavity, leading to diminished efficacy the nexttime the stick type product is used. This “contact-degrade-contact”cycle may be repeated every time the stick type product is used-leadingto most if not all applications after the first application being lessefficacious.

It is worth noting that articles of the present invention may beprovided in a unit-dose form that is used once and disposed ofsubsequently. This unit-dose form can provide several advantages overother product forms including stick type products, such as: 1) a highlevel of hygienic protection since it is used once and disposed of, 2)since the unit-dose form provides a pre-measured dose of the bleachingagent, in every dose, it takes the guesswork out of estimating how muchproduct to use (which can be confusing or even intimidating to consumerswho are not familiar with the product), and 3) since the solidhydrophilic particles can be distributed across the article, it canminimize spots that are over-treated or under-treated, and 4) since thebleaching agent, is not exposed to the environment or the oral cavityuntil the time of use, the potency of the bleaching agent, may bemaintained for longer periods of time.

In another aspect, articles of the present invention may be removed fromthe oral cavity after use. This, in contrast to stick type products,allows the user to remove and discard any bleaching agent leftover afterthe treatment period has been completed. The article of the presentinvention may be a single layer.

Hydrophobic Delivery Carrier

The solid article(s) as disclosed herein comprise a solid hydrophobicdelivery carrier combined with solid hydrophilic particles comprising atleast one bleaching agent embedded in the hydrophobic delivery carrier.The hydrophobic delivery carrier or article may be attached to the oralcavity by physical interference or mechanical inter-locking between thehydrophobic delivery carrier and the oral surfaces including the teeth.For example, the hydrophobic delivery carrier or article may be ofsufficient size that, once applied the hydrophobic delivery carrieroverlaps with the oral soft tissues rendering more of the teeth surfaceavailable for the treatment. The basic form of the hydrophobic deliverycarrier or article is a strip having a length and a width forming afirst and a second surface separated by a thickness from each other. Inaddition, the basic form of the hydrophobic delivery carrier or articlemay also be formed into any shape or size suitable to contact thedesired oral surface, for example into the form of a dental arch.

The form of said first surface may be substantially flat, may haveirregularities due to embedded solid hydrophilic particles, may beshaped into three dimensional shapes for example in the shape of adental arch or teeth, or combinations thereof. In general, the firstsurface and the second surface of the hydrophobic delivery carrier orarticle are similar in size and shape, adjacent to each other or nested,and separated by an average distance of no more than about 3 mm. Forexample, the average distance between the first surface and the secondsurface of the hydrophobic delivery carrier or article may be from about0.01 mm to about 3 mm, or from about 0.1 mm to about 2 mm, or from about0.15 mm to about 1 mm, or from about 0.25 mm to about 0.75 mm. Thehydrophobic delivery carrier may be a single layer.

The basic form of the hydrophobic delivery carrier is a strip having alength, a width, and a thickness. The average length of the hydrophobicdelivery carrier or article may be in the range from about 35 mm toabout 100 mm, or from about 40 mm to about 90 mm, or from about 50 mm toabout 80 mm. The average width of the hydrophobic delivery carrier orarticle may be in the range from about 3 mm to about 30 mm, or fromabout 5 mm to about 25 mm, or from about 15 mm to about 25 mm.

Without wishing to be bound by theory the average thickness of thehydrophobic delivery carrier or article may be a factor to ensure thatthe article: 1) is comfortable during use, and/or 2) releases aneffective amount of the bleaching agent per cm2 during use.Specifically, for a given % bleaching agent, if the average thickness ofthe hydrophobic delivery carrier or article is too low, the bleachingagent may be spread across a large area of a first surface andconsequently deliver a low level of bleaching agent per cm2 leading todecreased efficacy. In contrast, if the average thickness of thehydrophobic delivery carrier or article is too high, the article may betoo bulky and not comfortable during use. The average thickness of thehydrophobic delivery carrier or article may be in the range 0.01 mm toabout 3 mm, or from about 0.1 mm to about 2 mm, or from about 0.15 mm toabout 1 mm, or from about 0.25 mm to about 0.75 mm.

The hydrophobic delivery carrier may be transparent or translucent toelectromagnetic radiation with wavelengths from about 200 nm to about1700 nm.

Without wishing to be bound by theory the drop melting point of thehydrophobic delivery carrier may be a factor to ensure that thearticle: 1) does not melt or become sticky during storage, and/or 2)releases an effective amount of the bleaching agent during use.Specifically, if the drop melting point of the hydrophobic deliverycarrier is too low, the article may melt or become sticky duringstorage. In contrast, if the drop melting point of the hydrophobicdelivery carrier is too high, the article may not release an effectiveamount of the bleaching agent during use. For example, the drop meltingpoint of a suitable hydrophobic delivery carrier may be in the range offrom about 60° C. to about 120° C., or from about 70° to about 110° C.,or from about 80° C. to about 100° C., or from about 90° C. to about100° C.

Without wishing to be bound by theory, the needle penetrationconsistency value of the hydrophobic delivery carrier may be a factor toensure that the article: 1) does not become sticky during storage,and/or 2) releases an effective amount of the bleaching agent duringuse. Specifically, if the needle penetration consistency value of thehydrophobic delivery carrier is too high, the article may become stickyduring storage. In contrast, if the needle penetration consistency valueof the hydrophobic delivery carrier is too low, the article may notrelease an effective amount of the bleaching agent during use. Theneedle penetration consistency value of the hydrophobic delivery carriermay be in the range of from about 0.1 to about 100, or from about 0.5 toabout 50, or from about 1 to about 10.

Without wishing to be bound by theory, the cone penetration consistencyvalue of the hydrophobic delivery carrier may be a factor to ensure thatthe article: 1) does not become sticky during storage, and/or 2)releases an effective amount of the bleaching agent during use.Specifically, if the cone penetration consistency value of thehydrophobic delivery carrier is too high, the article may become stickyduring storage. In contrast, if the cone penetration consistency valueof the hydrophobic delivery carrier is too low, the article may notrelease an effective amount of the bleaching agent during use. The conepenetration consistency value of the hydrophobic delivery carrier may beless than about 10, or about 1 to about 9, or less than about 5.

The hydrophobic delivery carrier or article of the present invention maybe moldable. Being moldable may allow the hydrophobic delivery carrierto be shaped into the form of a dental arch or to the surface contour ofthe teeth. An optimal adaptation to the tooth surface allows 1) aneffective release of the bleaching agent and/or 2) a comfortableexperience during use. In one aspect, the permanent deformation occursunder minimum normal force being applied by the wearer, for example thehydrophobic delivery carrier or article substantially conforms to ashape of a tooth via permanent deformation under a pressure less thanabout 250,000 Pascals.

The hydrophobic delivery carrier of the present invention may be rigid.The rigidity of the hydrophobic delivery carrier or article may be afactor to ensure that 1) it is easy to handle and position accuratelyduring application, and/or 2) it keeps the given shape during use.Flexural stiffness is a material property that is a function of acombination of strip of material thickness, width and material modulusof elasticity. The test described below is a method for measuring therigidity of strips and sheeting. It determines the resistance to flexureof a sample by using a strain gauge affixed to the end of a horizontalbeam. The opposite end of the beam presses across a strip of the sampleto force a portion of the strip into a vertical groove in a horizontalplatform upon which the sample rests. A microammeter wired to the straingauge is calibrated in terms of deflection force. The rigidity of thesample is read directly from the microammeter and expressed as grams percentimeter of the sample strip width. Specifically, if the flexuralstiffness of the hydrophobic delivery carrier or article is too high, itmay not be moldable and may break during shaping at the tooth surface.In contrast, if the flexural stiffness of the hydrophobic deliverycarrier or article is too low, it may not be easy to handle and positionaccurately during application. For example, the flexural stiffness ofthe hydrophobic delivery carrier may be greater than 50 g/cm, or fromabout 75 g/cm to about 1000 g/cm, or from about 200 g/cm to about 500g/cm as measured by ASTM D2923-95.

The delivery carrier of the present invention is hydrophobic. Thehydrophobic delivery carrier of the present invention may bewater-insoluble. The hydrophobic delivery carrier of the presentinvention may comprise a wax, a polymer or a combination thereof. Waxesmay be thermoplastic. Suitable waxes which may be used for thehydrophobic delivery carrier may comprise microcrystalline wax or acombination of wax and a polymer. Examples of microcrystalline waxinclude the Multiwax series from Sonneborn (Parsippany, NJ), Crompton(Witco); these include Multiwax 835, Multiwax 440, Multiwax 180, andmixtures thereof. A suitable polymer which may be combined to form thehydrophobic delivery carrier may be for example polyethylene. Examplesof polyethylene include A-C 1702 or A-C 6702 made by Honeywell 25 Corp.(Morristown, NJ), with a penetration value of about 98.5 and about 90.0,respectively, under ASTM D-1321; polyethylene Performalene series fromBaker Hughes; this includes polyethylene Performalene 400 from BakerHughes Inc. (Houston, Tex.). For example, a ratio of weight percent ofpolymer divided by the weight percent of wax may be from about 0.01 toabout 100, from about 0.1 to about 10, from about 0.5 to about 2.Suitable examples for the hydrophobic delivery carrier of the presentinvention are waxes, for examples the casting waxes supplied by FreemanManufacturing Company, Ohio, USA, for example those listed in thefollowing table or a combination thereof.

Supplier reference Thickness Average thickness number (Gauge) mm +/−10%114024 14 1.58 114026 18 1.02 114007 20 0.86 114009 24 0.51 114010 260.39 114011 28 0.30 114012 30 0.25These wax sheets are moldable and readily conform to the shape of adental arch or tooth under manual pressure.

The delivery systems as used herein may comprise an adhesion means, suchthat they are capable of adhesion to oral surfaces, especially theteeth. This adhesion means may be provided by the present articlesherein or the adhesion means may be provided independently of thearticles herein (for example the adhesion means may be a separate phasefrom the articles herein where the articles may also have an adhesivemeans). The hydrophobic delivery carrier may be easily removed from theoral surfaces without the use of an instrument, a chemical solvent oragent or excess friction.

The hydrophobic delivery carrier may be held in place on the oralsurface by adhesive means and/or attachment provided by the hydrophobicdelivery carrier itself. For example, the hydrophobic delivery carriercan extend, attach, and adhere to the oral soft tissue. In addition, anadhesive can be applied to that portion of the hydrophobic deliverycarrier that may attach the article to the oral soft tissue. Thehydrophobic delivery carrier may also be attached to the oral cavity byphysical interference or mechanical inter-locking between thehydrophobic delivery carrier and the oral surfaces including the teeth.In addition, the hydrophobic delivery carrier may be held in place by anadhesion means that is independent of the article of the presentinventions herein, as disclosed in WO 03/015656.

Suitable adhesion means are known to the skilled person. When theadhesive means, if present, is provided by an adhesive, the adhesive maybe any adhesive which may be used to adhere materials to the toothsurface or to a surface of the oral cavity surfaces. Suitable adhesivesinclude, but are not limited to, skin, gum and muco adhesives, andshould be able to withstand the moisture, chemicals and enzymes of theoral environment for long enough for the oral care bleaching agents totake effect but may be soluble and/or biodegradable thereafter. Suitableadhesives may for example comprise water soluble polymers, hydrophobicand/or non-water-soluble polymers, pressure and moisture sensitiveadhesives, e.g. dry adhesives which become tacky upon contact with themouth environment, e.g. under the influence of moisture, chemicals orenzymes etc. in the mouth. Suitable adhesives include natural gums,synthetic resins, natural or synthetic rubbers, those gums and polymerslisted above under “Thickening Agents”, and various other tackysubstances of the kind used in known adhesive tapes, those known fromU.S. Pat. No. 2,835,628.

Solid Hydrophilic Particle

The present articles comprise a safe and effective amount of solidhydrophilic particles. The solid hydrophilic particles comprise ableaching agent as disclosed herein. For example, the amount of solidhydrophilic particles in the article may be from about 0.01% to about50%, or from about 0.1% to about 30%, or from about 0.2% to about 25%,by weight of the article.

In one aspect, it has been surprisingly found that better efficacyresults may be achieved if the solid hydrophilic particles are locatedheterogeneously in the hydrophobic delivery carrier, for example agreater number is located at a surface of the article that is intendedto contact the surface of the oral cavity to be treated, and lowernumber is located at the surface on the far side. Thus, the number ofthe solid hydrophilic particles per cm2 may be a factor to decreaseoral/topical irritation, decrease tooth-sensitivity and/or increaseefficacy during use. Without wishing to be bound by theory theheterogeneous distribution focuses the bleaching agent at the intendedsite of action thereby reducing the amount of bleaching agent and theunintended and sometimes negative side effects. Accordingly, if the sizeor number of solid hydrophilic particles is too large it may lead tolarge spots on oral/topical/tooth surfaces that are exposed to a highconcentration of the bleaching agent, which in turn may lead tooral/topical irritation and/or tooth-sensitivity and if the size ornumber of solid hydrophilic particles is too low efficacy may be toolow. The number of solid hydrophilic particles per cm2 at the firstsurface may be at least 5, or from about 5 to about 10000, or from about10 to about 1000, or from about 10 to about 100.

The number of solid hydrophilic particles at the second surface may belower than at the first surface. Generally, for a given particle size,the lower the number of solid hydrophilic particles at the secondsurface the better, as more bleaching agent is concentrated at theintended side and less bleaching agent is released towards theunintended parts of the oral cavity. For example, the average number ofthe solid hydrophilic particles per cm2 at the second surface may be atmost 200, or from about 0.01 to about 100, or from 1 to about 10.

The size of the individual solid hydrophilic particle may be a factor todecrease oral/topical irritation, or increase the intended effect, suchas bleaching efficacy. Without being bound by theory, if the size of thesolid hydrophilic particles is too large it may lead to large spots onoral/topical/tooth surfaces that are exposed to a high concentration ofthe bleaching agent, which in turn may lead to oral/topical irritationand/or tooth-sensitivity. For example, the number-averageequivalent-diameter or the volume-average equivalent-diameter of thesolid hydrophilic particles may be from about 0.001 microns to about5000 microns, or from about 0.01 microns to about 2000 microns, or 1micron to about 1000 microns. The number-average equivalent-diameter orvolume-average equivalent diameter of the solid hydrophilic particlescan be measured according to methods and equipment known in the art,such as those from Malvern Panalytical Ltd. (e.g. Malvern Mastersizer3000 particle size analysis equipment) or Horiba Ltd. (e.g. laser basedparticle size analysis equipment).

The article of the present invention comprises solid hydrophilicparticles embedded in the solid hydrophobic delivery carrier. In oneaspect it has been found that the solid hydrophilic particles may becomeflattened during the embedding process into the hydrophobic deliverycarrier. In one aspect, the particles may be pressed into an irregulardisc-like shape during the embedding process. Thereby, the surface areaof the solid hydrophilic particle which is exposed to the externalenvironment (e.g. the surface area of the solid hydrophilic particle atthe first surface of the hydrophobic delivery carrier) may be increased,potentially leading to more bleaching agent being released, and higherefficacy. This positive effect may be negatively affected, if thethickness of the hydrophobic delivery carrier is too large. In oneaspect, it has surprisingly been found that the ratio of the averagethickness of the hydrophobic delivery carrier and/or the article dividedby the number-average equivalent-diameter or the volume-averageequivalent-diameter of the solid hydrophilic particles may help boostthe efficacy of the bleaching agent. For example, the ratio of theaverage thickness of the hydrophobic delivery carrier and/or the articleto the number-average equivalent-diameter or the volume-averageequivalent-diameter of the solid hydrophilic particles may be from about0.001 to about 1000, from about 0.01 to about 100, or from about 0.1 toabout 10.

In articles wherein the solid hydrophilic particles are embedded in thehydrophobic delivery carrier, the configuration of the embeddedparticles (for example shape or location) may be a factor to ensurethat: 1) the embedded particles do not get detached from the hydrophobicdelivery carrier during storage, shipping or handling, and/or 2) theembedded particles release an effective amount of the bleaching agentduring use. Specifically, in articles wherein the solid hydrophilicparticles are embedded in the hydrophobic delivery carrier, if theembedded particles are configured such that a large portion (more thanabout 50% for example) of the embedded particle is above the surface ofthe hydrophobic delivery carrier, the embedded particle may get detachedfrom the hydrophobic delivery carrier during storage, shipping, orhandling. Furthermore, if a large portion of the embedded particleprotrudes above the surface of the hydrophobic delivery carrier, it mayincrease the roughness of the surface (for example similar to sand-paperin appearance or texture) and give the impression that it could lead todiscomfort to sensitive oral tissues even before the consumer uses it,or may even poke into sensitive oral tissues during application or useand lead to discomfort. In this regard, less than about 50%, or lessthan about 40%, or less than about 30%, or less than about 20%, of thevolume of the embedded solid hydrophilic particles is disposed above thesurface of the hydrophobic delivery carrier.

In addition, if embedded particles are configured such that a largeportion (more than 50% for example) of the embedded particle is belowthe surface of the hydrophobic delivery carrier and not exposed directlyto the external environment, it may not release an effective amount ofthe bleaching agent. In one aspect, it has been surprisingly found thatin articles wherein the solid hydrophilic particles are embedded in thehydrophobic delivery carrier, the embedded particles may be configuredsuch that 1) a large portion of the embedded particle is below thesurface of the hydrophobic delivery carrier, and, 2) a large portion ofthe surface of the embedded particle is exposed directly to the externalenvironment. This counterintuitive configuration of properties may 1)inhibit the embedded particles from getting detached from thehydrophobic delivery carrier, and, 2) release an effective amount of thebleaching agent from the embedded particles. For example, when particlesare embedded into the hydrophobic delivery carrier by distributing theparticles on a surface of the hydrophobic delivery carrier and pressingthe particles into the hydrophobic delivery carrier at a high pressure(for example in a hydraulic press, between two rollers, or between aroller and a hard surface), 1) a large portion of the particle may getdisposed below the surface, and 2) the particle itself may get at leastpartially flattened at or near the surface of the hydrophobic deliverycarrier such that a large portion of the surface of the particle isexposed directly to the external environment leading to the release ofan effective amount of the bleaching agent.

In articles wherein the solid hydrophilic particles are embedded in thehydrophobic delivery carrier, 1) more than about 50%, or more than about75%, or more than about 95%, or 100% of the volume of the embeddedparticles may be disposed below or at the surface of the hydrophobicdelivery carrier, and/or 2) more than about 10%, or more than about 20%,or more than about 30% of the surface area of the embedded particles isdisposed at the surface of the hydrophobic delivery carrier and therebyexposed directly to the external environment surrounding the hydrophobicdelivery carrier.

The size of the solid hydrophilic particles, thickness of the solidhydrophobic delivery carrier, or pressure applied may influence theconfiguration (for example shape or location) of the embedded particles.Solid hydrophilic particles may be embedded in the hydrophobic deliverycarrier by distributing the particles on a surface of the hydrophobicdelivery carrier and pressing the particles into the hydrophobicdelivery carrier at a pressure of at least about 50 pounds per squareinch (PSI), or at least about 500 PSI, or at least about 5000 PSI, or atleast about 50,000 PSI, or from about 50 PSI to about 50,000 PSI, orfrom about 50 PSI to about 5000 PSI, or from about 500 PSI to about 5000PSI.

The bleaching agent per solid hydrophilic particle may be from about 1%to about 95%, or from about 10% to about 50%, or from about 15% to about40% by weight of the solid hydrophilic particles.

It has been surprisingly found that the level of the bleaching agentrequired to achieve the intended effect in the present invention issurprisingly low, by weight of the article, for example lower thanconcentrations of bleaching agents usually used in the previouscommercial products.

The article of the present invention can comprise several differentbleaching agents as disclosed herein. The level of some active agentsmay be regulated and/or limited due to regulatory requirements, such asbleaching agents. For example, a suitable overall concentration ofbleaching agents as active agents may be from about 0.01% to about 15%,from 0.01% to 10.0%, less than 10%, from about 0.1% to about 7.5%, from0.1% to 5%, from about 0.1% to about 0.3%, from 0.1% to 3%, from about0.1% to less than 3% by weight of the article. The bleaching agentsprovided by the solid hydrophilic particles can be effective when usedeven at the low levels in the articles as disclosed herein.

Without wishing to be bound by theory it is believed that thesurprisingly high efficacy delivered by extremely low concentrations ofbleaching agents is achieved by the direct delivery of the bleachingagent at the surface in need of the treatment. Accordingly, theconcentration of the bleaching agent at the first surface (whichgenerally is the surface of the article that is intended to contact thesurface of the oral cavity to be treated) can be measured. For example,the concentration of the at least one bleaching agent at the firstsurface may be in the range from about 1 microgram/cm2 to about 10000micrograms/cm2, or from about 10 micrograms/cm2 to about 5000micrograms/cm2, or from about 50 micrograms/cm2 to about 3000micrograms/cm2 measured according to the method specified herein.

The concentration of the bleaching agent at the second surface of thearticle (which generally is opposite the first surface), may besignificantly lower than the concentration at the first surface. Forexample, the concentration of the at least one bleaching agent at thesecond surface may be from about 0.001 micrograms/cm2 to about 500micrograms/cm2, or from about 0.01 micrograms/cm2 to about 200micrograms/cm2, or from about 0.1 micrograms/cm2 to about 100micrograms/cm2 measured according to the method specified herein.

The ratio of the concentration of the bleaching agent at the firstsurface divided by the concentration of the bleaching agent at thesecond surface, as measured according to the procedure specified hereinmay be greater than 1, or from about 2 to about 10000, or from about 2to about 1000, or from about 2 to about 100.

In one aspect it has been surprisingly found that the solubility of thesolid hydrophilic particles in water, the ability to swell upon contactwith water, and/or the ability to release a bleaching agent upon contactwith water, may impact the efficacy of the article. For example, atleast about 20, 25, 30, 40, 50, 60, 70, or 80 parts by weight of thesolid hydrophilic particles may dissolve in about 100 parts by weight ofwater, or at least about 30 parts by weight of the solid hydrophilicparticles may dissolve in about 100 parts by weight of water, or 50parts, or 70 parts or 80 parts by weight of the solid hydrophilicparticles may dissolve in about 100 parts by weight of water. Withoutwishing to being bound by theory, it is believed the more soluble thesolid hydrophilic particles are, the higher their efficacy may be.Particles with a higher solubility may be delivered more effectively outof the hydrophobic delivery carrier to the tooth surface therebyincreasing the intended efficacy, such as for example bleaching. Anotherparameter of the solid hydrophilic particles that impacts the efficacyof the article may be swellability. For example, the solid hydrophilicparticles may swell by at least about 50%, 55%, 60%, 65%, 70%, 75% or80% upon contact with water, or the solid hydrophilic particles mayswell by at least about 60%, or at least about 70%, or at least about80% upon contact with water. Without being bound by theory, surprisinglythe amount of water available on the facial surface of the maxillaryanterior teeth to hydrate the solid hydrophilic particles and releasethe bleaching ingredients is low compared to the rest of the oralcavity. This may be especially important because the facial surfaces ofthe maxillary anterior teeth are the ones that are most visible whensmiling Thus, the solubility of the solid hydrophilic particles inwater, its ability to swell upon contact with water, or its ability torelease a bleaching agent upon contact with water can impact theefficacy of the article disproportionately on the “smile teeth” (facialsurface of the maxillary anterior teeth).

The solid hydrophilic particles are insoluble in the hydrophobicdelivery carrier of the present invention.

Bleaching Agents

The article of the present invention comprises a safe and effectiveamount of at least one bleaching agent comprised in the solidhydrophilic particles. Suitable bleaching agents may deliver hydrogenperoxide as an adduct or complex of hydrogen peroxide, or precursor tohydrogen peroxide. Examples of hydrophilic bleaching agent particlesinclude agents that provide bleaching effects, stain bleaching effects,stain removal effects, stain color change effects or any other effect,which change, or brighten tooth color. For example, hydrophilicbleaching agent particles include a source of peroxide radicals.Hydrophilic bleaching agent particles may include peroxides, metalchlorites, perborates, percarbonates, peroxyacids, persulfates,compounds that form the preceding compounds in situ, and combinationsthereof. Examples of peroxide compounds may include urea peroxide (alsoknown as carbamide peroxide or urea hydrogen peroxide adduct), calciumperoxide, and mixtures thereof. Examples of metal chlorites may includecalcium chlorite, barium chlorite, magnesium chlorite, lithium chlorite,sodium chlorite, potassium chlorite, and mixtures thereof. Examples ofhydrophilic bleaching agent particles may include hypochlorites (such asmetal hypochlorites). Examples of persulfates may include salts ofperoxymonosulfate, peroxydisulfate and mixtures thereof. Examples ofpersulfates, perborates, percarbonates, and hypochlorites includecorresponding salts of sodium, calcium, potassium, and other metals.Examples of suitable solid hydrophilic bleaching agent particlesinclude, but are not limited to complexes of hydrogen peroxide andpolyvinylpyrrolidone (PVP) polymers (also known as Peroxydone), ureaperoxide, and mixtures thereof, for example complexes of hydrogenperoxide and polyvinylpyrrolidone (PVP) polymers.

Further Additional and Optional Active Agents

The article of the present invention may further comprise a safe andeffective amount of at least one additional active agent, for examplethe solid hydrophilic particles may comprise a safe and effective amountof one or more additional active agents, and/or one or more additionalactive agents can be added to the hydrophobic delivery carrier separatefrom the solid hydrophilic particles. Suitable additional active agentsinclude any material that is generally considered safe for use in theoral cavity and that provides changes to the overall appearance and/orhealth of the oral cavity. For example suitable additional oral careactives may include one or more healing agent(s), anticalculus agent(s),fluoride ion source(s), antimicrobial agent(s), remineralizationagent(s), dentinal desensitizing agent(s), anesthetic agent(s),antifungal agent(s), coolants, anti-inflammatory agent(s), selective H-2antagonist(s), anticaries agent(s), nutrient(s), erythritol, probiotics,resolvins including eicosapentaenoic acid (EPA) and docosahexaenoic acid(DHA), as well as docosapentaenoic acid (DPA) clupanodonic acid,Resolvin D's RvD1 (7S,8R,17S-trihydroxy-DHA), RvD2(7S,16R,17S-trihydroxy-DHA), RvD3 (4S,7R,17S-trihydroxy-DHA), RvD4(4S,5,17S-trihydroxy-DHA), RvD5 (7S,17S-dihydroxy-DHA), and RvD6(4S,17S-dihydroxy-DHA) and Resolvin E's: RvE1(5S,12R,18R-trihydroxy-EPA), 18S-Rv1 (5S,12R,18S-trihydroxy-EPA), RvE2(5S,18R-dihydroxy-EPA), and RvE3 (17R,18R/S-dihydroxy-EPA), tranexamicacid, glycine, retinol, amino acids, such as for example histidine,isoleucine, leucine, lysine, methionine, phenylalanine, threonine,tryptophan, valine, alanine, asparagine, aspartic acid, glutamic acid,arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline,and serine, peptides, calcium salts of amino acids and peptides,niacinamide, human growth factors, and mixtures and/or combinationsthereof. The solid hydrophilic particle may contain at least oneadditional active agent at a level where upon directed use, the intendedbenefit is promoted without detriment to the oral surface to which it isapplied. Examples of the oral conditions these additional activesaddress include, but are not limited to, appearance and structuralchanges to teeth, for example reducing and/or removing, caries, plaque,tartar and stain, providing antibacterial effects, cavity prevention andtreatment, treatment of inflamed and/or bleeding gums, mucosal wounds,lesions, ulcers, aphthous ulcers, cold sores, tooth abscesses, theelimination of mouth malodor and improving breath resulting from theconditions above and other causes, such as microbial proliferation.

For example, the additional oral care active agent may be a healingagent that promotes or enhances the healing or regenerative process.Such healing agents may comprise hyaluronic acid or salts, glucosamineor salts, allantoin, curcumin, D panthenol, niacinamide, ellagic acid,flavonoids (including fisetin, querctin, luteolin, apigenin), vitamin E,ubiquinone, or mixtures thereof.

The additional oral care active agent may be one or moreanti-inflammatory agent(s) including, but not limited to, non-steroidalanti-inflammatory agents such as acetyl salicylic acid, ketorolac,flurbiprofen, ibuprofen, naproxen, indomethacin, acetaminophen, acetylsaliscylic acid, steroids, ketorolac, naproxen, ketoprofen, piroxicamand meclofenamic acid, COX-2 inhibitors such as valdecoxib, celecoxiband rofecoxib, and mixtures thereof. If present, the anti-inflammatoryagents generally comprise from about 0.001% to about 5% by weight of thearticles.

The additional oral care active agent may be one or more probioticsselected from Lactobacillus reuteri ATCC 55730; Lactobacillus salivariusstrain TI12711 (LS 1); Lactobacillus paracasei ADP-1; Streptococcussalivarius K12; Bifidobacterium DN-173 010; Filtrate of L. paracaseistrain (pro-t-Action™); S. Oralis KJ3, S. rattus JH145, S. uberis KJ2;Lactobacillus, reuteri Prodentis; Lactobacillus salivarius LS1;Lactobacillus paracasei; Lactobacillus paracasei ADP1; Streptococcussalivarius M18, K12 or BLIS K12 and BLIS M18; BacillusAmyloliquefaciens; Bacillus Clausii; Bacillus Coagulans; BacillusSubtilis; Bacillus subtilis: E-300; Bifidobacterium Animalis;Bifidobacterium B6; Bifidobacterium Bifidum; Bifidobacterium Breve(Bb-03); Bifidobacterium DN-173 010; Bifidobacterium GBI 30 6068;Bifidobacterium infantis; Bifidobacterium Lactis; Bifidobacterium lactisBb-12; Bifidobacterium Longum; Bifidobacterium Thermophilum;Enterococcus Faecalis; Enterococcus Faecium; Enterococcus Faecium NCIMB10415; Enterococcus LAB SF 68; Lactobacilli reuteri ATCC 55730 and ATCCPTA 5289; Lactobacilli reuteri ATCC 55730 and ATCC PTA 5289 (10:1);Lactobacillus Acidophilus; Lactobacillus acidophilus ATCC 4356 andBifidobacterium bifidum ATCC 29521; Lactobacillus acidophilus;Bifidobacterium longum; Bifidobacterium bifidum; Bifidobacterium lactis;Lactobacillus Brevis; Lactobacillus Casei (subsp. Casi); Lactobacilluscasei Shirota; Lactobacillus Confusus; Lactobacillus crispatus YIT12319; Lactobacillus Curvatus; Lactobacillus Delbrueckii Ssp. BulgaricusPXN 39; Lactobacillus Fermentum; Lactobacillus fermentum YIT 12320;Lactobacillus Gasseri; Lactobacillus gasseri YIT 12321; LactobacillusHelveticus; Lactobacillus Johnsonii; Lactobacillus Kimchii;Lactobacillus Lactis L1A; Lactobacillus Paracasei (Lpc37); Lactobacillusparacasei GMNL-33; Lactobacillus Pentosus; Lactobacillus plantarum;Lactobacillus Plantarum; Lactobacillus Protectus; Lactobacillus Reuteri;Lactobacillus reuteri ATCC 55730; Lactobacillus reuteri SD2112(ATCC55730); Lactobacillus Rhamnosus (GG); Lactobacillus rhamnosus GG;Lactobacillus rhamnosus GG; L. rhamnosus LC705; Propionibacteriumfreudenreichii ssp; shermanii JS; Lactobacillus rhamnosus L8020;Lactobacillus rhamnosus LB21; Lactobacillus Salivarius; Lactobacillussalivarius WB21; Lactobacillus Sporogenes; Lactococcus Lactis SspDiacetylactis; Lactococcus Lactis Ssp. Lactis; Pediococcus Acidilactici;Pediococcus Pentosaceus; Saccharomyces Boulardii; SaccharomycesCerevisiae; Strep. uberis KJ2sm; Strep. oralis KJ3sm; trep. rattusJH145; Streptococcus mitis YIT 12322; Streptococcus Oralis KJ3;Streptococcus Rattus JH145; Streptococcus Salivarius (BLIS K12 or BLISM18); Streptococcus salivarius K12; Streptococcus Thermophilus;Streptococcus Uberis KJ2; Thermus thermophiles; Weissella cibaria CMS2;Weissella cibaria CMS3; and Weissella cibaria CMU.

Probiotics can be used in the articles of the present invention topromote positive oral health effects, such as reduce caries and plaque,promote gum health, improve breath, and promote whitening. The efficacyof probiotics in the articles can be determined for example by measuringone or more of the following: reduction of the levels of salivary mutansstreptococci; reduction of gingival crevicular fluid; reduction ofperiodontal pathogens (C. rectus and P. gingivitis) in subgingivalplaque; decreased counts of yeast; decreased prevalence of oral candida;reduction of oral volatile sulfur compound (VSC) levels; and reductionof TNF-α and IL-8 production. Without being limited to theory it isbelieved that one or more of the above positive oral health effects maybe achieved through the production of bacterial toxins, which remove orreduce certain types of bacteria in the oral cavity; further one or moreof the above positive oral health effects may be achieved throughbacterial production of one or more enzymes that inhibit the productionof or dissolves/loosens biofilms or sticky deposits that can lead tooral health problems.

For example, at least one anti-calculus agent may be used in thearticles as disclosed herein. The anticalculus agent may be selectedfrom the group consisting of polyphosphates and salts thereof; polyaminopropane sulfonic acid (AMPS) and salts thereof; polyolefin sulfonatesand salts thereof; polyvinyl phosphates and salts thereof; polyolefinphosphates and salts thereof; diphosphonates and salts thereof;phosphonoalkane carboxylic acid and salts thereof; polyphosphonates andsalts thereof; polyvinyl phosphonates and salts thereof; polyolefinphosphonates and salts thereof; polypeptides; and mixtures thereof,wherein the mentioned salts are usually alkali metal salts. For exampleanticalculus agents, such as pyrophosphates, polyphosphates,polyphophonates and mixtures thereof, may also show a stabilizing effectto the solid hydrophilic particles comprising a bleaching agent.

The anticalculus agent may be for example a polyphosphate. Apolyphosphate is generally understood to comprise two or more phosphatemolecules arranged primarily in a linear configuration, although somecyclic derivatives may be present. Linear polyphosphates correspond to(X PO₃)_(n) where n is about 2 to about 125, wherein preferably n isgreater than 4, and X is for example sodium, potassium, etc. For (XPO₃)_(n) a when n is at least 3 the polyphosphates are glassy incharacter. Counter-ions for these phosphates may be the alkali metal,alkaline earth metal, ammonium, C₂-C₆ alkanolammonium and salt mixtures.Polyphosphates are generally employed as their wholly or partiallyneutralized water-soluble alkali metal salts such as potassium, sodium,ammonium salts, and mixtures thereof. The inorganic polyphosphate saltsinclude alkali metal (e.g. sodium) tripolyphosphate, tetrapolyphosphate,dialkyl metal (e.g. disodium) diacid, trialkyl metal (e.g. trisodium)monoacid, potassium hydrogen phosphate, sodium hydrogen phosphate, andalkali metal (e.g. sodium) hexametaphosphate, and mixtures thereof.Polyphosphates larger than tetrapolyphosphate usually occur as amorphousglassy materials, such as those manufactured by FMC Corporation whichare commercially known as Sodaphos (n≈6) Hexaphos (n≈13), Glass H(n≈21), and mixtures thereof. The level of polyphosphates in the presentarticles may be from about 1.5% to about 10%, for example from about 2%to about 10%, or from about 6% to about 10%, by weight of the article.

The pyrophosphate salts useful in the present articles include, alkalimetal pyrophosphates, di-, tri-, and mono-potassium or sodiumpyrophosphates, dialkali metal pyrophosphate salts, tetraalkali metalpyrophosphate salts, and mixtures thereof. For example, thepyrophosphate salt may be selected from the group consisting oftrisodium pyrophosphate, disodium dihydrogen pyrophosphate (Na₂H₂P₂O₇),dipotassium pyrophosphate, tetrasodium pyrophosphate (Na₄P₂O₇),tetrapotassium pyrophosphate (K₄P₂O₇), and mixtures thereof, whereintetrasodium pyrophosphate is preferred. Tetrasodium pyrophosphate may bethe anhydrous salt form or the decahydrate form, or any other speciesstable in solid form in the present articles. The salt is in its solidparticle form, which may be its crystalline and/or amorphous state, withthe particle size of the salt being small enough to be aestheticallyacceptable and readily soluble during use. The level of pyrophosphatesalt in the present articles may be from about 1.5% to about 10%, forexample from about 2% to about 10%, or from about 3% to about 8%, byweight of the article. The phosphate sources, including but are notlimited to, polyphosphates and pyrophosphates, are described in moredetail in Kirk & Othmer, Encyclopedia of Chemical Technology, FourthEdition, Volume 18, Wiley-Interscience Publishers (1996), pages 685-707.

Polyolefin phosphonates include those wherein the olefin group contains2 or more carbon atoms. Polyvinylphosphonates includepolyvinylphosphonic acid. Diphosphonates and salts thereof includeazocycloalkane-2,2-diphosphonic acids and salts thereof, ions ofazocycloalkane-2,2-diphosphonic acids and salts thereof (such as thosewhich the alkane moiety has five, six or seven carbon atoms, in whichthe nitrogen atom is unsubstituted or carries a lower alkylsubstitutent, e.g. methyl), azacyclohexane-2,2-diphosphonic acid,azacyclopentane-2,2-diphosphonic acid,N-methyl-azacyclopentane-2,3-diphosphonic acid, EHDP(ethanehydroxy-1,1,-diphosphonic acid), AHP(azacycloheptane-2,2-diphosphonic acid, a.k.a.1-azocycloheptylidene-2,2-diphosphonic acid),ethane-1-amino-1,1-diphosphonate, dichloromethane-diphosphonate, etc.Phosphonoalkane carboxylic acid or their alkali metal salts include PPTA(phosphonopropane tricarboxylic acid), PBTA(phosphonobutane-1,2,4-tricarboxylic acid), each as acid or alkali metalsalts.

Antimicrobial antiplaque agents may be used as suitable additionalactive agents of the present invention and may include, but are notlimited to, triclosan, hops acids from hops extracts, such as hops alphaacids, including, humulone, adhumulone, cohumulone, posthumulone,prehumulon, and combinations thereof, or hops beta acids, including,lupulone, adlupulone, colupulone, and combinations thereof,5-chloro-2-(2,4-dichlorophenoxy)-phenol, as described in The MerckIndex, 11th ed. (1989), pp. 1529 (entry no. 9573) in U.S. Pat. No.3,506,720, and in European Patent Application No. 0,251,591;chlorhexidine (Merck Index, no. 2090), alexidine (Merck Index, no. 222;hexetidine (Merck Index, no. 4624); sanguinarine (Merck Index, no.8320); benzalkonium chloride (Merck Index, no. 1066); salicylanilide(Merck Index, no. 8299); domiphen bromide (Merck Index, no. 3411);cetylpyridinium chloride (CPC) (Merck Index, no. 2024;tetradecylpyridinium chloride (TPC); N-tetradecyl-4-ethylpyridiniumchloride (TDEPC); octenidine; delmopinol, octapinol, and otherpiperidino derivatives; cocomidyl propyl betaine, sodium cocomidylglutamate, sodium lauryl sarcosinate, GTF inhibitors, povidone iodinedelmopinol, propolis, phthalic acid and its salts, monoperthalic acidand its salts and esters, ascorbyl stearale, oleoyl saicosine, alkylsulfate. The articles may comprise effective antimicrobial amounts ofessential oils, herbal extracts, and combinations thereof for examplecitral, geranial, rosemary extract, tea extract, magnolia extract,eucalyptol geraniol. carvacrol, citral, hinokitol. catechol, methylsalicylate, epigallocatechin gallate, epigallocatechin. gallic acid,miswak extract, sea-buckthorn extract, and combinations of menthol,eucalyptol, thymol and methyl salicylate; antimicrobial metals and saltsthereof; for example those providing zinc ions, stannous ions, copperions, and/or mixtures thereof; bisbiguanides, or phenolics; antibioticssuch as augmentin, amoxicillin, tetracycline, doxycycline, minocycline,and metronidazole; and analogs and salts of the above antimicrobialantiplaque agents and/or anti-fungals such as those for the treatment ofCandida albicans. If present, these additional active agents generallyare present in a safe and effective amount for example from about 0.1%to about 5% by weight of the present articles.

In another aspect, anticaries agent(s) may be a suitable additionalactive agent for the articles of the present invention. The anticariesagent may be selected from the group consisting of fluoride, sodiumfluoride, potassium fluoride, titanium fluoride, hydrofluoric acid,amine fluoride, sodium monofluorophosphate, ammonium fluoride, stannousfluoride, stannous chloride, stannous gluconate, copper salts, copperchloride, copper glycinate, zinc chloride, zinc lactate, zinc citrate,zinc phosphate, sodium iodide, potassium iodide, calcium chloride,calcium lactate, calcium phosphate, hydroxyapatite, fluoroapatite,amorphous calcium phosphate, crystalline calcium phosphate, sodiumbicarbonate, sodium carbonate, calcium carbonate, oxalic acid,dipotassium oxalate, monosodium monopotassium oxalate, caseinphosphopeptides, casein phosphopeptide coated hydroxy apatite, bioglasscontaining one or more of SiO₂, CaO, Na₂O, P₂O₅, CaF₂, B₂O₃, K₂O, MgO,such as those disclosed in U.S. Pat. No. 5,735,942. If present, theinstant articles provide from about 50 ppm to 10,000 ppm, or from about100 to 3000 ppm, of fluoride ions in the articles as disclosed herein.

Nutrients, such as minerals, may improve the teeth and the tooth surfaceand thus may be used as suitable additional active agent with thearticles as disclosed herein. Suitable minerals are e.g. calcium,phosphorus, fluoride, zinc, manganese, potassium and mixtures thereof.These minerals are e.g. disclosed in Drug Facts and Comparisons (looseleaf drug information service), Wolters Kluer Company, St. Louis, Mo.,©1997, pp 10-17.

As such, the articles as disclosed herein deliver a high ratio of theconcentration in weight percent of the bleaching agent, such as hydrogenperoxide present in the solid hydrophilic particles to the concentrationin weight percent of bleaching agent, present in the overall article.This results from the high concentration in weight percent of bleachingagent present in the solid hydrophilic particles combined with arelatively low concentration in weight percent of bleaching agentpresent in the overall article. Without being bound by theory, inaspects of the present invention comprising hydrogen peroxide, thissurprising combination of seemingly contradictory parameters deliversthe hydrogen peroxide to the tooth surface with a high driving forceeven when the overall concentration or amount of hydrogen peroxidedelivered to the tooth surface is low. As a result, the high drivingforce delivers a surprisingly high level of bleaching efficacy and/orbleaching speed; while the low overall concentration or low amount ofbleaching agent delivered to the tooth surface may help reduce toothsensitivity. For example, the ratio of the concentration in weightpercent of bleaching agent present in the solid hydrophilic particles tothe concentration in weight percent of bleaching agent present in theoverall article may be from about 2 to about 50000, or from about 3 toabout 10000, or from about 5 to about 1000.

The bleaching agents of the present invention may be stabilized againstdegradation by the shielding effect of the hydrophobic delivery carrier.Further stabilizing agents for the bleaching agent may be present in thearticles as disclosed herein. Bleaching agents may be further stabilizedagainst degradation by the article. Therefore, stabilizing agents may beadded to the present article. Suitable stabilizing agents are forexample ortho-phosphoric acid, phosphate(s), such as sodium hydrogenphosphate, pyrophosphate(s), organophosphonate(s),Ethylenediaminetetraacetic acid, Ethylenediamine-N,N′-diacetic acid,Ethylenediamine-N,N′-disuccinic acid, potassium stannate, sodiumstannate, tin salts, zinc salts, salicylic acid,1-Hydroxyethylidene-1,1-diphosphonic acid, and combinations thereof. Forexample, stabilizers may be used which show additional oral careeffects, such as anti-tartar effect, produced by phosphates as disclosedherein, for example pyrophosphate, tripolyphosphate, hexametaphosphate,phytic acid, salts of PO₃(PO₂)_(n) PO3 where n=2-30, phosphoric acid,gantrez, zinc salts including zinc citrate, zinc lactate, zinc chloride,zinc phosphate, zinc oxide, enzymes such as dextransess, xylanases,proteases, phosphonates such as bis-phosphonate, chelants such as EDTA,Calcium Sodium EDTA, Citrate, citric acid, oxalic acid, oxalate salts,polymers (such as those disclosed in U.S. application Ser. No.16/216,329), PVP, polyacryclic acid (carbopol), polyacrylates, stannoussalts, stannic salts. A stabilizing agent may be present in an articleof the present invention in an amount from about 0.0000001%, 0.000001%,or 0.00001%, to about 0.00001%, 0.0001%, or 0.01% by weight of thearticle. For example, a stabilizing agent may be present in an articleof the present invention in an amount from about 0.0001%, or 0.01% toabout 0.01%, 0.1% or about 1% by weight of the solid hydrophilicparticles.

A stabilizing agent may also include chelants. The chelant may be acopper, iron and/or manganese chelants, or a mixture thereof. Suitablechelants may be selected from: diethylene triamine pentaacetate,diethylene triamine penta(methyl phosphonic acid), ethylenediamine-N′N′-disuccinic acid, ethylene diamine tetraacetate, ethylenediamine tetra(methylene phosphonic acid), hydroxyethane di(methylenephosphonic acid), and any combination thereof. A suitable chelant may beselected from ethylene diamine-N′N′-disuccinic acid (EDDS),hydroxyethane diphosphonic acid (HEDP) or mixtures thereof. Thestabilizer may comprise ethylene diamine-N′N′-disuccinic acid or saltthereof. The ethylene diamine-N′N′-disuccinic acid may be in S,Senantiomeric form. The stabilizer may comprise4,5-dihydroxy-m-benzenedisulfonic acid disodium salt, glutamicacid-N,N-diacetic acid (GLDA) and/or salts thereof,2-hydroxypyridine-1-oxide, Trilon P™ available from BASF, Ludwigshafen,Germany. Suitable chelants may also be calcium carbonate crystal growthinhibitors, such as 1-hydroxyethanediphosphonic acid (HEDP);N,N-dicarboxymethyl-2-aminopentane-1,5-dioic acid;2-phosphonobutane-1,2,4-tricarboxylic acid; and salts thereof; and anycombination thereof. A stabilizer may comprise a hydroxamate chelant,such as hydroxamic acid or a corresponding salt, for example cocohydroxamic acid (Axis House RK 853).

The article as disclosed herein may comprise optional additionalingredients. For example, a further optional ingredient may be presentin the article which is intended to be released from the second side,e.g. the far side of the hydrophobic delivery carrier. For examplecoolants, desensitizing agents, numbing agents and/or taste and/oraesthetics improving agent(s), such as flavoring agents can be used asoptional ingredients in articles of the present invention, for exampleat a level of from about 0.001% to about 10%, or from about 0.1% toabout 1%, by weight of the article. Coolants, desensitizing agents andnumbing agents may decrease potential negative perceptions, such astingling, burning etc. provoked by a bleaching agent. A wide variety ofmaterials can be used as coolants, including, but are not limited tocarboxamides, menthol, ketals, diols, and mixtures thereof. Optionalcoolants in the present articles may be the paramenthan carboxyamideagents such as N-ethyl-p-menthan-3-carboxamide (known as “WS-3”),N,2,3-trimethyl-2-isopropylbutanamide (known as “WS-23”), menthol,3-1-menthoxypropane-1,2-diol (known as TK-10), menthone glycerol acetal(known as MGA) menthyl lactate (known as Frescolat®), and mixturesthereof. The terms menthol and menthyl as used herein include dextro-and levorotatory isomers of these compounds and racemic mixturesthereof. Desensitizing or anti-pain agent may include, but are notlimited to, strontium chloride, potassium nitrate, natural herbs such asgall nut, Asarum, Cubebin, Galanga, scutellaria, Liangmianzhen, Baizhi,etc. Suitable numbing agents include benzocaine, lidocaine, clove budoil, and ethanol.

Suitable flavoring agents include oil of wintergreen, oil of peppermint,oil of spearmint, clove bud oil, menthol, anethole, methyl salicylate,eucalyptol, 1-menthyl acetate, sage, eugenol, parsley oil, oxanone,alpha-irisone, marjoram, lemon, orange, propenyl guaethol, cinnamon,vanillin, thymol, linalool, cinnamaldehyde glycerol acetal (known asCGA), and mixtures thereof. If present the flavoring agents aregenerally used at levels of from about 0.01% to about 10%, for examplefrom about 1% to about 5%, more or from about 1.5% to about 2%, byweight of the article.

The present articles may optionally comprise sweetening agents includingsucralose, sucrose, glucose, saccharin, dextrose, levulose, lactose,mannitol, sorbitol, fructose, maltose, xylitol, saccharin salts,thaumatin, aspartame, D-tryptophan, dihydrochalcones, acesulfame andcyclamate salts, especially sodium cyclamate and sodium saccharin, andmixtures thereof. If present, the article contains from about 0.1% toabout 10% of these agents, for example from about 0.1% to about 1%, byweight of the article.

Dyes, pigments, colorants, and mixtures thereof may optionally beincluded in the present article to give the articles colored appearance.An advantage of adding pigments and/or colorants to the articles hereinis that it will allow the user to see if the article covers their teethevenly and completely, since coverage is easier to see with a coloredarticle. The colorant may provide color similar to the color of bleachedteeth. Colorants useful herein are stable with the bleaching agent andare those recognized as safe. The levels of dye, pigments and colorantsthat are optionally used herein are in the range of about 0.001% toabout 15%, for example from about 0.01% to about 10% or from about 0.1%to about 5% by weight of the article.

In one aspect, two or more oral care active agents that are normallyincompatible with each other may be separately combined in the samearticle of the present invention. The solid hydrophobic delivery carriercan thus maintain separation of such incompatible active agents. Forexample, the present invention may comprise a hydrophilic bleachingagent combined with an additional oral care active agent that furtherimproves the bleaching efficacy of the article. Examples includebleaching agents combined with additional oral care actives that mayprovide a driving force to increase the pH when contacted with water.Specifically, examples include solid hydrophilic particles comprisingperoxides separately combined with sodium bicarbonate (baking soda) inthe solid hydrophobic delivery carrier. When in contact, peroxide andbaking soda are reactive towards one another, and when separately addedto the solid hydrophobic delivery carrier of the present invention canbe maintained separated from each other until use. While not wishing tobe bound by theory it is hypothesized that particles of two or morehydrophilic oral care active agents that are normally incompatible witheach other are kept substantially separated from each other inhydrophobic delivery carrier—this separation even on a microscopicscale, may minimize or eliminate the incompatibility. Furthermore, it ishypothesized that when particles of one of the hydrophilic oral careagents come in contact with moisture, for example at the time of use inthe oral cavity, the components of the particles may at least partiallydissolve or swell and make direct contact with components of theparticles of the other oral care agents; however, this may happenprimarily at the time of use in the oral cavity, and only minimally ornot at all prior to that in the article. Thus, the article of thepresent invention may comprise two or more oral care active agents thatare normally incompatible with each other.

To the extent oral care active agents are desired to be incorporated inthe solid hydrophilic particles of the present invention, but the oralcare active agent is typically provided as a solid particle that hasrelatively low water solubility (e.g. less than about 20, or less thanabout 15, parts by weight of the solid particles dissolve in about 100parts by weight of water), such oral care active agent can besolubilized in a suitable solvent (e.g. water, glycerin, or the like),then incorporated in a solid hydrophilic particle (e.g. a PVP solidhydrophilic particle), and then the resulting solid hydrophilic particlecomprising the oral care active agent being incorporated into the oralcare article of the present invention.

To the extent oral care active agents are desired to be incorporated inthe solid hydrophilic particles of the present invention, but the oralcare active agent is typically provided as a liquid material, such oralcare active agent can be incorporated in a solid hydrophilic particle(e.g. a PVP solid hydrophilic particle), and then the resulting solidhydrophilic particle comprising the oral care active agent beingincorporated into the oral care article of the present invention.

Identifying Indicia

The oral care articles of the present invention can further compriseidentifying indicia to assist a user of the article to apply the correctside of the article to the user's teeth. The user may apply the firstsurface of the article (as described herein) to the teeth of user, whilethe second surface faces away from the user's teeth. Identifying indiciacan be in the form of words, logos, trademarks, trade names, or thelike, and printed or embossed on a surface of the oral care articleitself or on packaging for the oral care article. Identifying indiciacan also include coloring the first surface of the article a differentcolor from the second surface of the article. As such, in one aspect,the oral care article further comprises identifying indicia todistinguish, for example visually distinguish, the first surface of thearticle from the second surface of the article.

Bleaching Efficacy

The bleaching efficacy of the articles of the present invention, asmeasured per the clinical protocol disclosed herein and calculated as−Δb* is surprisingly high and may be at least at least about 0.25, or atleast about 0.5, or at least about 1.0, or at least about 1.5, or atleast about 2, or at least about 2.5, or at least about 3, or at leastabout 3.5, or at least about 4. Generally, a change in yellowness, asmeasured per the clinical protocol as disclosed herein, and calculatedas −Δb* of at least 0.25 is noticeable.

For example, the present invention may deliver a surprisingly high ratioof bleaching efficacy, as measured per the clinical protocol disclosedherein, and calculated as −Δb*, to the weight percent of bleaching agentpresent in the overall article. For example, a −Δb* of 1.5 with anarticle containing 3%, by weight of the article, of bleaching agent,would deliver a ratio of bleaching efficacy, as measured per theclinical protocol as disclosed herein, and calculated as −Δb*, to theweight percent of bleaching agent present in the overall article of 0.5.For example, the ratio of bleaching efficacy of the present invention,as measured per the clinical protocol disclosed herein, and calculatedas −Δb* to the weight percent of bleaching agent present in the overallarticle may be, at least about 2.5, or at least about 5, or at leastabout 10, or at least about 15.

For example, the present invention may deliver: 1) a surprisingly highratio of bleaching efficacy, as measured per the clinical protocol asdisclosed herein, and calculated as −Δb*, to the fraction ofparticipants who reported oral irritation or were observed to have oralirritation that was possibly or probably attributed to the articletested; 2) a surprisingly high ratio of bleaching efficacy, as measuredper the clinical protocol as disclosed herein, and calculated as −Δb*,to the fraction of participants who reported tooth sensitivity that waspossibly or probably attributed to the article; or 3) a surprisinglyhigh ratio of bleaching efficacy, as measured per the clinical protocolas disclosed herein, and calculated as −Δb*, to the fraction ofparticipants who reported tooth sensitivity and reported oral irritationor were observed to have oral irritation that was possibly or probablyattributed to the article.

For example, the ratio of bleaching efficacy of the present invention,as measured per the clinical protocol as disclosed herein, andcalculated as −Δb*, to the fraction of participants who report toothsensitivity, oral irritation or both or are observed to have toothsensitivity, oral irritation or both that is possibly or probablyattributed to the present invention may be at least at least about 6, orat least about 8, or at least about 10, or at least about 15, or atleast about 20, or at least about 25, or at least about 50.

Clinical Protocol

The bleaching efficacies of the oral compositions comprising bleachingagents are measured using the following clinical protocol. Per treatmentgroup, 17 to 25 participants are recruited to complete the clinicalstudy when testing oral compositions with less than about 1% bleachingagent, and 8 to 25 participants when testing oral compositions with atleast about 1% bleaching agent. Recruited participants must have fournatural maxillary incisors with all measurable facial sites. The meanbaseline L* of the group of participants must be from 71 to 76, and themean baseline b* of the group of participants must be from 13 to 18. Inaddition, participants with malocclusion on maxillary anterior teeth,severe or atypical intrinsic staining, such as that caused bytetracycline, fluorosis or hypo-calcification, dental crowns orrestorations on the facial surfaces of maxillary anterior teeth,self-reported medical history of melanoma, current smoking or tobaccouse, light-sensitivity or a pigmentation skin disorder, self-reportedtooth sensitivity, or previous tooth whitening using a professionaltreatment, over-the-counter kit, or investigational product, areexcluded from the study. Participants are provided with take-home kitswith Crest Cavity Protection toothpaste and Oral-B Indicator soft manualtoothbrush (both from Procter & Gamble, Cincinnati, Ohio, USA) to beused twice a day in the customary manner.

The participants use a toothbrush (“Anchor 41 tuft white toothbrush”from Team Technologies, Inc. Morristown, Tenn., USA) to brush theirteeth with water for 30 seconds prior to being treated with the oralcomposition. The maxillary anterior teeth of each participant aretreated with the oral composition for 60 minutes once daily. If the oralcomposition to be assessed is a semisolid gel, from 0.6 g to 0.8 g ofthe oral composition is applied across a film of clear flexiblepolyethylene 66 mm×15 mm in size and from about 0.01 mm to about 0.02 mmthick prior to applying to the maxillary anterior teeth. If the oralcomposition to be assessed is a solid article, the article is applieddirectly to the maxillary anterior teeth.

If the oral composition is used with electromagnetic radiation:

-   -   1) After 50 minutes of treatment with the oral composition, the        electromagnetic radiation is applied toward the facial surfaces        of the maxillary anterior teeth for 10 minutes;    -   2) The electromagnetic radiation is directed toward the        maxillary anterior teeth through the oral composition;    -   3) The hydrophobic delivery carrier needs to allow at least        about 90% of the electromagnetic radiation from 400 nm to 500 nm        to pass through; and    -   4) The electromagnetic radiation is delivered via four        fiber-optic cables (model number M71L01 from Thorlabs, Newton,        N.J., USA) connected to four high power LEDs with a peak        intensity wavelength of 455 nm (model number M455F1 from        Thorlabs, Newton, N.J., USA) as shown in FIG. 9 . The four LEDs        are run at 1000 mA each using an LED Driver and Hub (model        numbers DC4104 and DC4100-HUB from Thorlabs, Newton, N.J., USA).        The exit ends of the four fiber-optic cables are mounted behind        a transparent mouthpiece to help position the electromagnetic        radiation reproducibly against the outer surface of the        hydrophobic delivery carrier. The exit ends of the four        fiber-optic cables are about 7 mm away from the exit surface of        the mouthpiece with the electromagnetic radiation passing        through the transparent mouthpiece. The bite-shelf of the        mouthpiece is offset such that the transparent window through        which the electromagnetic radiation passes toward the maxillary        anterior teeth is 7.4 mm high. Also, the transparent window        through which the electromagnetic radiation passes toward the        maxillary anterior teeth is 40 mm long measured linearly from        end to end (not including the curvature). The exit ends of the        fiber-optic cables are positioned and angled such that the cones        of electromagnetic radiation exiting from the fiber-optic cables        are centered within the transparent window through which the        electromagnetic radiation passes toward the maxillary anterior        teeth as shown in FIG. 9 . Also, the exit ends of the four        fiber-optic cables are spaced such that the cones of        electromagnetic radiation are spaced across the length of the        transparent window through which the electromagnetic radiation        passes toward the maxillary anterior teeth as shown in FIG. 9 .        The intensity of the electromagnetic radiation from 445 nm to        465 nm measured at the central axis of each cone of        electromagnetic radiation exiting at the exit surface of the        transparent window through which the electromagnetic radiation        passes toward the maxillary anterior teeth needs to be from        about 175 mW/cm² to about 225 mW/cm² as measured by the method        disclosed herein.

Once 60 minutes of the treatment with the oral composition is completed,the polyethylene film is removed in the case of a semi-solid gel, or thearticle is removed in the case of a solid article. This treatment isapplied once daily for a minimum of 7 days for oral compositions withless than about 1% bleaching agent, and a minimum of 3 days for oralcompositions with at least about 1% bleaching agent.

The change in tooth color due to the treatment with the oral compositionis measured using the procedure described below the day after the 7^(th)treatment for oral compositions with less than about 1% bleaching agentand after the 3^(rd) treatment for oral compositions with at least about1% bleaching agent.

Tooth color is measured using a digital camera having a lens equippedwith a polarizer filter (Camera model no. CANON EOS 70D from Canon Inc.,Melville, N.Y. with NIKON 55 mm micro-NIKKOR lens with adapter). Thelight system is provided by Dedo lights (model number DLH2) equippedwith 150 watt, 24V bulbs model number (Xenophot model number HL X64640),positioned about 30 cm apart (measured from the center of the externalcircular surface of one of the glass lens through which the light exitsto the other) and aimed at a 45 degree angle, such that the light pathsintersect at the vertical plane of the chin rest about 36 cm in front ofthe focal plane of the camera. Each light has a polarizing filter (Lee201 filter), and a cutoff filter (Rosco 7 mil Thermashield filter fromRosco, Stamford, Conn., USA).

At the intersection of the light paths, a fixed chin rest is mounted forreproducible repositioning in the light field. The camera is placedbetween the two lights such that its focal plane is about 36 cm from thevertical plane of the chin rest. Prior to beginning the measurement oftooth color, color standards are imaged to establish calibrationset-points. A Munsell N8 grey standard is imaged first. The whitebalance of the camera is adjusted, such that the RGB values of grey are200. Color standards are imaged to get standard RGB values of the colorchips. The color standards and grey standard are listed below (fromMunsell Color, Division of X-rite, Grand Rapids, Mich., USA). Each colorstandard is labeled with the Munsell nomenclature. To create a grid ofcolor standards they can be arranged in the following manner. Thisenables multiple color standards to be contained in a single imagecaptured of the grid of color standards.

Color Standard Grid 1

Color standard grid 1 7.5R 6 8 2.5R 6 10 10YR 6.5 3 POLARIZATION 5R 7 8N 3.5 0 CHECK 7.5RP 6 6 10R 5 8 5YR 7 3 2.5Y 8.5 2 2.2YR 6.47 4.1 7.5YR7 4 5YR 8 2 N 8 0 10R 7 4 N 8 0 5YR 7.5 2.5 2.5Y 8 4 5YR 7 3.5 5YR 7 2.55YR 5 2 5YR 7.5 2 N 6.5 0 N 9.5 0Color Standard Grid 2

Color standard grid 2 5YR 7.5 3.5 2.5Y 6 4 10YR 7.5 3.5 2.5R 7 8 7.5R 78 10YR 7.5 2 10YR 7.5 2.5 N 5 0 2.5R 6 8 10YR 7 2 5R 7 4 10YR 7 2.5 N6.5 0 7.5RP 6 8 7.5R 8 4 5Y 8 1 7.5YR 8 2 2.2YR 6.47 4.1 N 5 0 2.5Y 8 410YR 7 3 N 9.5 0 10RP 7 4 2.5Y 7 2Color Standard Grid 3

Color standard grid 3 5R 6 10 N 8.5 0 10YR 6.5 3.5 10RP 6 10 N 8 0 7.5YR7 3 2.5Y 3.5 0 10YR 7 3.5 5Y 8.5 1 5YR 8 2.5 5YR 7.5 3 5R 5 6 10YR 7.5 35YR 6.5 3.5 2.5YR 5 4 2.5Y 8 2 10YR 8 2 2.5Y 7 2 2.5R 6 6 5R 7 6 10YR 82.5 10R 5 6 N 6.5 0 7.5YR 8 3

For baseline tooth color, participants use a toothbrush (“Anchor 41 tuftwhite toothbrush” from Team Technologies, Inc. Morristown, Tenn., USA)to brush their teeth with water to remove debris from their teeth. Eachparticipant then uses cheek retractors (from Washington ScientificCamera Company, Sumner, Wash., USA; treated with at frosted matte finishat A&B Deburring Company, Cincinnati, Ohio, USA) to pull the cheeks backand allow the facial surfaces of their teeth to be illuminated. Eachparticipant is instructed to bite their teeth together such that theincisal edges of the maxillary incisors contact the incisal edges of themandibular incisors. The participants are then positioned on the chinrest at the intersection of the light paths in the center of the cameraview and the tooth images are captured. After all participants areimaged, the images are processed using image analysis software (Optimasmanufactured by Media Cybernetics, Inc. of Silver Spring, Md.). Thecentral four incisors are isolated and the average RGB values of theteeth are extracted.

After the participants have used a whitening product, but prior tocapturing participant's tooth images, the system is set to the baselineconfiguration and calibrated as previously discussed. After calibration,each participant is imaged a second time using the same procedure asbefore making sure the participant is in the same physical position asthe pre-treatment image including orientation of the teeth. The imagesare processed using the image analysis software to obtain the averageRGB values of the central four maxillary incisors. The RGB values of allof the images are then mapped into CIE L*′a*b* color space using the RGBvalues and the L*a*b* values of the color chips on the color standard.The L*a*b* values of the color chips on the color standard are measuredusing a Photo Research SpectraScan PR650 from Photo Research Inc., LAusing the same lighting conditions described for capturing digitalimages of the facial dentition. The PR650 is positioned the samedistance from the color standards as the camera. Each chip isindividually measured for L*a*b* after calibration according to themanufacturer's instructions. The RGB values are then transformed intoL*a*b* values using regression equations such as:L*=25.16+12.02*(R/100)+11.75*(G/100)−2.75*(B/100)+1.95*(G/100)³a*=−2.65+59.22*(R/100)−50.52*(G/100)+0.20*(B/100)−29.87*(R/100)²+20.73*(G/100)²+8.14*(R/100)³−9.17(G/100)³+3.64*[(B/100)²]*[/100]b*=−0.70+37.04*(R/100)+12.65*(G/100)−53.81*(B/100)−18.14*(R/100)²+23.16*(G/100)*(B/100)+4.70*(R/100)³−6.45*(B/100)³The R² for L*, a*, and b* should be >0.95. Each study should have itsown equations.

These equations are generally valid transformations in the area of toothcolor (60<L*<95, 0<a*<14, 6<b*<25). The data from each participant's setof images is then used to calculate product whitening performance interms of changes in L*, a* and b* −a standard method used for assessingwhitening benefits. When evaluating oral compositions with less thanabout 1% bleaching agent: Changes in L* is defined asΔL*=L*_(day after 7 treatments)−L*_(baseline) where a positive changeindicates improvement in brightness; Changes in a* (red-green balance)is defined as Δa*=a*_(day after 7 treatments)−a*_(baseline) where anegative change indicates teeth which are less red; Changes in b*(yellow-blue balance) is defined asΔb*=b*_(day after 7 treatments)−b*_(baseline) where a negative changeindicates teeth are becoming less yellow. When evaluating oralcompositions with at least about 1% bleaching agent: Changes in L* isdefined as ΔL*=L*_(after 3 treatments)−L*_(baseline) where a positivechange indicates improvement in brightness; Changes in a* (red-greenbalance) is defined as Δa*=a*_(after 3 treatments)−a*_(baseline) where anegative change indicates teeth which are less red; Changes in b*(yellow-blue balance) is defined asΔb*=b*_(after 3 treatments)−b*_(baseline) where a negative changeindicates teeth are becoming less yellow. −Δb* is used as the primarymeasure of bleaching efficacy. The overall color change is calculated bythe equation ΔE=(ΔL*²+Δa*²+Δb*²)^(1/2).

After using the whitening products, color changes in CIE Lab color spacecan be calculated for each participant based on the equations given.

Process of Making Oral Care Articles

The present invention further relates to a process of making an oralcare article comprising the steps of: (i) providing a solid hydrophobicdelivery carrier in the form of a strip having a length and a widthforming a first surface and having a thickness extending from the firstsurface to a second surface, wherein the average thickness is less thanabout 3 mm; (ii) applying solid hydrophilic particles comprising ableaching agent to the first surface of the solid hydrophobic deliverycarrier, for example at a level of from about 0.01% to about 15%, bytotal weight of the solid hydrophobic delivery carrier and solidhydrophilic particles; and (iii) forcing the solid hydrophilic particlesinto the first surface of the solid hydrophobic delivery carrier,thereby embedding the solid hydrophilic particles into the solidhydrophobic delivery carrier.

In one aspect, the particles are forced into the first surface of thesolid hydrophobic delivery carrier under a pressure of at least about 50pound per square inch (PSI), or at least about 500 PSI, or at leastabout 5000 PSI, or at least about 50,000 PSI.

In one aspect, the solid hydrophilic particles are applied only to thefirst surface of the solid hydrophobic delivery carrier (i.e. the solidhydrophilic particles are not applied to the second surface of the solidhydrophobic delivery carrier).

Materials present on the market, such as casting wax clear sheet 24gauge (reference number 114009 supplied by Freeman ManufacturingCompany, Ohio, USA) can be used as the hydrophobic delivery carrier ofthe present invention.

The solid hydrophilic particles may be forced or embedded in thehydrophobic delivery carrier by any suitable procedure, for example:

-   -   1. The solid hydrophilic particles may be sifted or deposited        onto the hydrophobic delivery carrier and pressed in a hydraulic        press for a specified period of time at a specified pressure,        for example 60 seconds at 625 PSI causing the solid hydrophilic        particles to become embedded in the hydrophobic delivery        carrier. The material may then be cut into a suitable shape, for        example a strip.    -   2. The solid hydrophilic particles may be sifted or deposited        onto the hydrophobic delivery carrier and pressed via nip        rollers at a specified pressure or gap, causing the solid        hydrophilic particles to become embedded in the hydrophobic        delivery carrier.    -   3. A photoreceptor drum (in combination with a corona wire and        laser for example) may be used to acquire a selective surface        charge that attracts the solid hydrophilic particles at the        desired quantity. The photoreceptor drum may then be used to        deposit the solid hydrophilic particles onto the hydrophobic        delivery carrier, which may then be passed between nip rollers        to embed the solid hydrophilic particles in the hydrophobic        delivery carrier.    -   4. The surface of the hydrophobic delivery carrier may be at        least partially melted (for example via a hot air stream) and        immediately after the solid hydrophilic particles may be sifted        or deposited onto the said partially molten surface. The        hydrophobic delivery carrier may then be cooled (for example via        exposure to ambient air) such that the said molten hydrophobic        delivery carrier re-solidifies around at least a portion of the        solid hydrophilic particles, embedding them in the hydrophobic        delivery carrier.

The present invention further relates to a process for making an oralcare article wherein the solid hydrophilic particles may be disposedwithin the hydrophobic delivery carrier by any suitable procedure, forexample:

-   -   1. The material of the hydrophobic delivery carrier may also be        at least partially melted or softened and the solid hydrophilic        particles may be incorporated within the said partially melted        or softened material by mixing or kneading. The material may        then be cooled or solidified and shaped in a suitable form, for        example a strip.    -   2. The solid hydrophilic particles may also be incorporated        within the material of the hydrophobic delivery carrier by        repeatedly folding the hydrophobic delivery carrier over the        solid hydrophilic particles and compressing it back into a sheet        in a hydraulic press. The material may then be shaped into a        suitable form, for example a strip.    -   3. The material of the hydrophobic delivery carrier may be        softened via warming until it becomes plastic, for example at        about 50° C. At a plastic temperature, it can be mixed with the        solid hydrophilic particles, for example in a single screw        extruder, twin screw extruder, z-blade mixer, or similar        equipment suitable for processing viscous materials. The mixture        of plastic hydrophobic delivery carrier and solid hydrophilic        particles can then be shaped into a suitable form, such as a        strip or a tray, via conventional shape-forming technologies        such as extrusion, injection molding, thermoforming, etc.    -   4. The material of the hydrophobic delivery carrier may be        melted, for example at 80° C., before being mixed with the solid        hydrophilic particles using conventional mixing equipment. The        melted mixture can then be shaped into a suitable form, such as        a strip or a tray, via conventional shape-forming technologies        such as casting or injection molding.

The oral care article of the present invention can be a unit-dosearticle and/or a removable article. Suitable examples of an “unit-dosearticle” and/or an “removable article” include casting wax clear sheet24 gauge (reference number 114009 supplied by Freeman ManufacturingCompany, Ohio, USA) combined with solid hydrophilic particles comprisingat least one bleaching agent and a) cut into a strip about 0.51 mmthick, about 22 mm wide and about 62 mm long, or b) pre-formed into adental tray. Examples of products that are not “unit-dose article” or“removable articles” include stick type products (for example lip balmor lipstick)—because these are generally not single use products, norare they generally removed from the oral cavity.

Referring now to the drawings, FIG. 1A shows an article 10 fordelivering bleaching agent(s) provided by solid hydrophilic particles 20in a hydrophobic delivery carrier 12 as disclosed herein to the teethand the oral cavity. The hydrophobic delivery carrier 12 is in stripform and comprises a surface having a width W from about 50 to about 80mm and a length L from about 15 to 25 mm. The bulk of the hydrophobicdelivery carrier 12 has an average thickness T from about 0.15 to about1.0 mm. The hydrophobic delivery carrier 12 in FIG. 1A is shaped instrip form which is substantially flat and may have rounded corners. Asuitable strip may be a casting wax clear sheet 24 gauge (referencenumber 114009 supplied by Freeman Manufacturing Company, Ohio, USA) cutinto a strip about 0.51 mm thick, about 22 mm wide and about 62 mm long.Solid hydrophilic particles 20 are disposed within and embedded in thehydrophobic delivery carrier 12 and some are located close to thesurface and/or some of them may be in direct contact with theenvironment.

FIG. 1B shows another embodiment of an article 10 for delivering activesagent(s) provided by solid hydrophilic particles 20 in a hydrophobicdelivery carrier 12 as disclosed herein to the teeth and the oralcavity. The hydrophobic delivery carrier 12 in FIG. 1B is in strip forma with rounded corners. The strip comprises a first surface 14 having awidth W from about 50 to about 80 mm and a length L from about 15 to 25mm and second surface 16 on the opposite site of the hydrophobicdelivery carrier 12. First surface 14 and second surface 16 are spacedby the bulk of the hydrophobic delivery carrier 12 having an averagethickness T from about 0.15 to about 1.0 mm A suitable strip may be acasting wax clear sheet 24 gauge (reference number 114009 supplied byFreeman Manufacturing Company, Ohio, USA) cut into a strip about 0.51 mmthick, about 22 mm wide and about 62 mm long. The solid hydrophilicparticles 20 are embedded into the hydrophobic delivery carrier 12 inFIG. 1B so that at least some of the solid hydrophilic particles 20 arelocated close to the first surface 14 and/or some of them may be indirect contact with the environment and/or may slightly protrude fromthe first surface 14. In contrast to the first surface 14 the secondsurface 16 shows less or no solid hydrophilic particles 20.

The solid hydrophilic particles 20 used in the articles 10 shown inFIGS. 1A and 1B may contain or are themselves a bleaching agent capableof influencing or effecting a desired change in appearance or structureof the surface it contacts. As discussed previously, example bleachingagents include: peroxide, for example complexes of hydrogen peroxide andpolyvinylpyrrolidone (PVP) polymers, urea peroxide, and mixturesthereof. Examples of appearance and structural changes include, but arenot necessarily limited to: stain bleaching, stain removal, plaqueremoval, and tartar removal.

FIG. 2A shows a cross-sectional view, taken along section line 2-2 ofthe hydrophobic delivery carrier 12 shown in FIG. 1A. Thereby it can beseen that the solid hydrophilic particles 20 are distributed irregularlyinside the bulk of the hydrophobic delivery carrier 12. The solidhydrophilic particles 20 may be located also close to a surface of thehydrophobic delivery carrier 12 or may come into direct contact with theexternal environment.

FIG. 2B shows a cross-sectional view, taken along section line 2-2 ofthe hydrophobic delivery carrier 12 shown in FIG. 1B. Thereby it can beseen that the concentration of the solid hydrophilic particles 20 at thefirst surface 14 is greater than the concentration of the solidhydrophilic particles 20 at the second surface 16 of the hydrophobicdelivery carrier 12. In the article shown in FIG. 2B second surface 16is nearly free of solid hydrophilic particles 20.

FIGS. 3 and 4 show an article 10 of the present invention applied to thetooth surface of a plurality of adjacent teeth 22. The article 10 may beapplied to the tooth surface after it has been shaped or before (FIG. 3). For example, the article 10 may be applied to the teeth with a forcesufficient to shape the hydrophobic delivery carrier 12 such that it atleast partially conforms to the shape of the teeth 22 such as shown inFIG. 3 . Embedded in adjacent soft tissue 24 is a plurality of adjacentteeth 22 (FIG. 4 ). Adjacent soft tissue 24 herein defined as softtissue surfaces surrounding the tooth structure including: papilla,marginal gingival, gingival sulcus, inter dental gingival, and gingivalgum structure on lingual and buccal surfaces up to and includingmuco-gingival junction on the pallet. In both FIGS. 3 and 4 , thearticle 10 is in form of a strip, wherein the first surface 14comprising the higher concentration of solid hydrophilic particles 20 isarranged that it faces the teeth 22. The material of the hydrophobicdelivery carrier 12 of the article 10 may have a thickness and flexuralstiffness such that it can conform to the contoured surfaces of teeth 22and to adjacent soft tissue 24. Thus, the hydrophobic delivery carrier12 may have sufficient flexibility to form to the contours of the oralsurface, the surface being a plurality of adjacent teeth 22, wherein thearticle 10 can be applied without significant pressure. A suitablematerial for the hydrophobic delivery carrier 12 of an article 10 may bea casting wax (reference number 114009 supplied by Freeman ManufacturingCompany, Ohio, USA).

The hydrophobic delivery carrier 12 serves as a protective barrier forthe bleaching agent provided by the solid hydrophilic particles 20 atthe first surface 14. It prevents leaching or erosion of the bleachingagent via the second surface 16 for example, by the wearer's tongue,lips, and saliva. This allows the solid hydrophilic particles 20 to actupon the tooth surfaces 22 of the oral cavity for the intended period oftime, for example from several minutes to several hours.

FIG. 5A is a photograph image of casting wax clear sheet 24 gauge(reference number 114009 supplied by Freeman Manufacturing Company,Ohio, USA) cut into a strip about 22 mm wide and about 62 mm long. Saidstrip can be directly used as hydrophobic delivery carrier 12 or thehydrophobic delivery carrier 12 is formed into a dental tray (FIGS. 5Band 5C). In one aspect, the first surface 14 of the hydrophobic deliverycarrier 12 comprising the higher concentration of the solid hydrophilicparticles 20 may be located at the inside of the dental tray facing thetooth surface during use., and the second surface 16 may be located atthe outside of the dental tray facing the soft tissue and the tongueduring use. The hydrophobic delivery carrier 12 can be formed intodental tray form with (FIG. 5C) or without (FIG. 5B) a notch 18.

FIG. 6 is a photograph image (of Example IV-A) of a sheet of casting wax(reference number 114009 supplied by Freeman Manufacturing Company,Ohio, USA) usable as hydrophobic delivery carrier 12 comprising embeddedsolid hydrophilic particles 20. FIG. 7 shows the same example (IV-A) ina microscope image (4× magnification).

FIG. 8A and FIG. 8B are a set of microscope images (4× magnification)that show the differences between a first surface 14 Vs. a secondsurface 16 of Example V-A. In FIG. 8A, the solid hydrophilic particles20 are clearly visible at a first surface—exposed directly to theexternal environment. In contrast in FIG. 8B, the solid hydrophilicparticles 20 appear to be below the second surface 16—not exposeddirectly to the external environment.

Methods of Using Oral Care Articles

The present invention further relates to a method of using the oral carearticles of the present invention. The oral care article can be appliedto the teeth of a consumer in the dental office by a dental professionalor can be used at home by the consumer. Generally, the recommendedtreatment period is a sufficient period of time to achieve the desiredeffect of the bleaching agent, i.e. to achieve the desired grade ofbleaching.

In practicing the present invention, the user applies the article hereinthat contains the bleaching agent to obtain the desired effect, such as,whitening, to one or more teeth. The article can be applied with anysuitable auxiliary means, or even with the fingers. The articles hereinmay be almost unnoticeable when applied to the teeth. After a desiredperiod of time has elapsed, the residual article may be easily removedfrom the tooth surface. In general, it is not necessary to prepare theteeth before applying the present article. For example, the user maychoose to brush the teeth or rinse the mouth before applying thearticles of the present invention, but the surfaces of the oral cavityare neither required to be clean, nor to be dried nor to be excessivelywet with saliva or water before the application.

The above-described articles and delivery systems may be combined in akit which comprises: 1. present article and 2. instructions for use; orwhich comprises: 1. present article, and 2. instructions for use. If thetooth shall be radiated by electromagnetic radiation, the kit mayfurther comprise an electromagnetic radiation source of the appropriatewavelength and instruction for use, so that the kit can be used byconsumers in a convenient manner

Optional Electromagnetic Radiation Treatment

The article as disclosed herein comprising bleaching agents may be usedto whiten/bleach teeth and/or removing stain from tooth surfaces. Thebleaching efficacy may be further increased by directing electromagneticradiation of a suitable wavelength toward at least one tooth. A devicesuitable to provide such electromagnetic radiation is shown in FIG. 9 .Electromagnetic radiation will be applied to the articles 10 asdisclosed herein, if the effectiveness of the bleaching agent providedby the solid hydrophilic particles 20 can be increased by theelectromagnetic radiation. For example, electromagnetic radiation with apeak intensity wavelength of about 455 nm may increase bleachingefficacy of a bleaching or whitening agent, such as peroxide.

A suitable wavelength may be any wavelength, which corresponds to amaximum absorption band of the tooth and/or the tooth stain to bebleached. For example, the article may be radiated with anelectromagnetic radiation with one or more wavelengths in the range offrom about 200 nm to about 1200 nm. The electromagnetic radiation may bedirected toward at least one tooth. For example, more than one tooth maybe irradiated. For example, the electromagnetic radiation may have apeak intensity at a wavelength in the range of from about 400 nm toabout 500 nm, or from about 425 nm to about 475 nm, or from about 445 nmto about 465 nm, or wherein the peak intensity wavelength of theelectromagnetic radiation is similar to the wavelength at which thestain absorbs the most electromagnetic radiation. Electromagneticradiation may be directed toward at least one tooth for partial or wholewearing time of the article; or after the article has been removed fromthe tooth. Electromagnetic radiation may be applied at least for asufficient period of time for whitening or a sufficient period of timeto achieve the desired effect of the bleaching agent, e.g. for at leastabout 1 minute, for at least about 5 minutes, or for at least about 10min. The electromagnetic radiation may be applied using the proceduredisclosed in US 2013/0295525. The article as disclosed herein is appliedto at least one tooth and maintained on the at least one tooth for afirst period of time; after the first period of time electromagneticradiation is directed toward the at least one tooth for a second periodof time, wherein the first period of time has a duration greater than50%, or 80% of a total duration of the first and second periods of time;and finally, the article is removed from the at least one tooth.

Suitable sources of electromagnetic radiation include the sourcedescribed herein in the section titled “Clinical Protocol”.

The articles as disclosed herein may be transparent or translucent toelectromagnetic radiation with wavelengths from about 400 nm to about500 nm. For example, the articles as disclosed herein when applied in anaverage thickness of from about 0.05 mm to about 2 mm, or in the rangeof from about 0.1 mm to about 1.0 mm, or in the range from about 0.25 mmto about 0.75 mm allow from about 10%, 20%, or 30% to about 40%, 50%,60%, 70%, 80%, 90%, or 100% of electromagnetic radiation from about 400nm to about 500 nm to pass through, as measured by a spectrophotometer.

The electromagnetic radiation impinging on the surface of the tooth orouter surface of the hydrophobic delivery carrier, in the wavelengthrange from about 400 to about 500 nm may range in intensity from about 5mW/cm2 to about 500 mW/cm2, or from about 10 mW/cm2 to about 300 mW/cm2,or from about 175 mW/cm2 to about 250 mW/cm2 measured according to theprocedure specified herein.

Procedure to Measure Intensity of Electromagnetic Radiation

The intensity of the electromagnetic radiation can be measured using aspectrometer (USB 2000+ from Ocean Optics) connected to a UV-VIS 200micron fiber-optic cable with a cosine corrector at the tip (OP200-2-UV-VIS from Ocean Optics). The spectrometer is connected to acomputer running the spectrometer software (Oceanview 1.3.4 from OceanOptics). The tip of the fiber-optic cable is held pointing toward thelight source at the location where the light intensity is to bemeasured. The photons collected at the detector surface are guided viathe fiber-optic cable to the charge-coupled device in the spectrometer(CCD). The CCD counts photons arriving to the CCD during apre-determined time period at each wavelength from 200 nm to 1100 nm anduses a software algorithm to convert these photon counts to spectralirradiance (mW/cm²/nm). The spectral irradiance is integrated from 200nm to 1100 nm by the software to yield the Absolute Irradiance (mW/cm²),which is the intensity of electromagnetic radiation from 200 nm to 1100nm. The spectral irradiance is integrated from 400 nm to 500 nm by thesoftware to yield the Absolute Irradiance (mW/cm²), which is theintensity of electromagnetic radiation from 400 nm to 500 nm.

For consumer convenience, the article as disclosed herein may beprovided as a Kit comprising the article as disclosed herein, anoptional electromagnetic radiation source emitting electromagneticradiation in a suitable wavelength, and instructions for use.

The articles of this invention are useful for both human and otheranimals (e.g. pets, zoo, or domestic animals) applications.

EXAMPLES

The following non-limiting example III-A, III-B, III-C and V-A furtherdescribe example articles within the scope of the present invention; inaddition, supporting examples I-A, II-A, II-B, II-C, II-D, II-E, IV-A,VI-A, VI-B, and VII-A made using principles of the present invention(with higher % bleaching agent), further demonstrate advantages of thepresent invention. Many variations of the examples are possible withoutdeparting from the scope of the invention. All examples were performedat room temperature (RT) and atmospheric pressure unless statedotherwise.

These examples were made by 1) weighing the casting wax sheet, 2)sifting the solid hydrophilic particles (complex of hydrogen peroxideand polyvinylpyrrolidone, urea peroxide, or sodium percarbonate) ontothe casting wax sheet through a USA Standard Testing Sieve Number 40with 425 micron opening, 3) sandwiching the wax sheet and particlesbetween two sheets of paper and non-stick release liner, 4) placing thesandwich in a hydraulic press and applying a pressure of 625 psi for 60seconds, 5) removing the wax sheet now embedded with particles andweighing it to calculate the weight of particles embedded. These sheetsmay be cut into shapes and sizes suitable for use in the oral cavity,for example about 22 mm wide and about 62 mm long.

I-A II-A II-B II-C II-D II-E Casting wax sheet 26-gauge¹ (grams) 3.6253— — — — — Casting wax sheet 24-gauge² (grams) — 5.091 5.002 5.03755.0355 5.0359 Complex of hydrogen peroxide and 0.6397 1.0531 0.91051.0567 1.0511 1.0039 polyvinylpyrrolidone³ (grams) % H2O2 2.77 3.17 2.853.21 3.19 3.07 % Hydrophilic particles 15.00 17.14 15.40 17.34 17.2716.57 ¹Casting wax sheet 26-gauge, reference number 114010, averagethickness of about 0.39 mm, about 10 cm × about 10 cm square, suppliedby Freeman Manufacturing Company, Ohio, USA ²Casting wax sheet 24-gauge,reference number 114009, average thickness of about 0.51 mm, about 10 cm× about 10 cm square, supplied by Freeman Manufacturing Company, Ohio,USA ³Peroxydone K-30, from Ashland Global Specialty Chemicals Inc.,Covington, KY. Solubility >40 parts per 100 parts of water (estimatedfrom information provided in Product Data Sheet from supplier onpolyvinylpyrrolidone polymer K-30). Sieved through USA Standard TestingSieve Number 40 with 425 micron opening. Contains about 17% to 20%(median 18.5%) H2O2 per information from supplier.

III-A III-B III-C IV-A V-A Casting wax sheet 26-gauge¹ (grams) — — —3.6072 Casting wax sheet 24-gauge² (grams) 5.007 4.9543 4.9179 — 4.9782Complex of hydrogen peroxide and 0.0274 0.0286 0.0326 0.104 0.0168polyvinylpyrrolidone³ (grams) % H2O2 0.10 0.11 0.12 0.52 0.06 %Hydrophilic particles 0.54 0.57 0.66 2.80 0.34 ¹Casting wax sheet26-gauge, reference number 114010, average thickness of about 0.39 mm,about 10 cm × about 10 cm square, supplied by Freeman ManufacturingCompany, Ohio, USA ²Casting wax sheet 24-gauge, reference number 114009,average thickness of about 0.51 mm, about 10 cm × about 10 cm square,supplied by Freeman Manufacturing Company, Ohio, USA ³Peroxydone K-30,from Ashland Global Specialty Chemicals Inc., Covington, KY.Solubility >40 parts per 100 parts of water (estimated from informationprovided in Product Data Sheet from supplier on polyvinylpyrrolidonepolymer K-30). Sieved through USA Standard Testing Sieve Number 40 with425 micron opening. Contains about 17% to 20% (median 18.5%) H2O2 perinformation from supplier.

VI-A VI-B Casting wax sheet 24-gauge¹ (grams) 4.9286 5.0906 UreaPeroxide² (grams) 0.4733 0.4848 % H2O2 3.10 3.08 % Hydrophilic particles8.76 8.69 ¹Casting wax sheet 24-gauge, reference number 114009, averagethickness of about 0.51 mm, about 10 cm × about 10 cm square, suppliedby Freeman Manufacturing Company, Ohio, USA ²Urea Hydrogen PeroxideAdduct, Catalog number L13940 from Alfa Aesar, Ward Hill, MA. Solubilityin water of 800 grams per liter at 20 C. per Safety Data Sheet fromsupplier (80 parts per 100 parts of water). Sieved through USA StandardTesting Sieve Number 40 with 425 micron opening. Contains about 35.4%H2O2 per Wikipedia dated Sep. 22, 2020.

VII-A Casting wax sheet 24-gauge¹ (grams) 5.0586 Sodium percarbonate²(grams) 0.5058 % H2O2 2.95 % Hydrophilic particles 9.09 ¹Casting waxsheet 24-gauge, reference number 114009, average thickness of about 0.51mm, about 10 cm × about 10 cm square, supplied by Freeman ManufacturingCompany, Ohio, USA ²Sodium Percarbonate, Catalog number A16045 from AlfaAesar, Ward Hill, MA. Solubility in water of 150 grams per liter (15parts per 100 parts of water) - information from Wikipedia dated May 21,2018. Calculated to contain about 32.5% H2O2. Sieved through USAStandard Testing Sieve Number 40 with 425 micron opening.

COMPARATIVE EXAMPLES

Comparative Crest 3D White Strips, manufactured by The Procter & ExampleI-A Gamble Company, Cincinnati, OH, USA. Ingredients: Water, Glycerin,9.5% H2O2, Carbomer, PVP, PEG, Acrylate copolymer, NaOH, Saccharin, andPyrophosphate.Bleaching Efficacy

The bleaching efficacy of Example I-A (with electromagnetic radiation)Vs. Comparative Example I-A (with electromagnetic radiation) measuredaccording to the ex-vivo procedure specified herein are listed in TABLE1.

TABLE 1 Bleaching Efficacy Comparative Example I-A Example I-A % H₂O₂2.77 9.5 Description Solid particles of H2O2 dissolved PVP-peroxide inaqueous embedded in wax polymeric gel. delivery carrier Averagereduction in 2.9  2.8 yellowness (−Δb* after one treatment)

TABLE 1 shows that Example I-A delivered a similar level of reduction inyellowness (−Δb*) Vs. Comparative Example I-A (−Δb* of 2.9 Vs. 2.8) eventhough Example I-A had less % bleaching agent (2.77% Vs. 9.5%). Theseresults clearly demonstrate the surprisingly similar level of efficacyof Example I-A (particles of PVP-peroxide embedded in wax deliverycarrier) vs. Comparative Example I-A (H₂O₂ dissolved in aqueouspolymeric gel), even though Example I-A had less than ⅓^(rd) the %bleaching agent of Comparative Example I-A. These results clearlydemonstrate the surprisingly large impact of solid hydrophilic particlescomprising bleaching agent embedded in hydrophobic wax delivery carrieron efficacy.

The bleaching efficacy of Example III-A, III-B, and III-C (samples takenfrom all three batches) (with electromagnetic radiation) and ComparativeExample I-A (with electromagnetic radiation) measured according to theex-vivo procedure specified herein are listed in Table 2.

TABLE 2 Bleaching Efficacy Example III-A, III-B, and III-C (samplestaken Comparative from all three batches) Example I-A % H₂O₂ About 0.1%9.5 Description Solid particles of H2O2 dissolved PVP-peroxide inaqueous embedded in a solid polymeric gel wax delivery carrier Averagereduction in 2.19 (after three 2.8 (after one yellowness (−Δb*)treatments) treatment)

TABLE 2 shows that Example III-A, III-B, and III-C after threetreatments delivered only slightly less reduction in yellowness (−Δb*)compared to Comparative Example I-A after one treatment (2.19 Vs. 2.8)even though Example III-A, III-B and III-C had less % bleaching agent(about 0.1% Vs. 9.5%). Specifically, these results show that ExampleIII-A, III-B, and III-C after three treatments surprisingly deliveredabout 78% of the reduction in yellowness of Example I-A after onetreatment—this is even more surprising since Examples III-A, III-B, andIII-C had only about 1% of the % bleaching agent as Comparative ExampleI-A. These results clearly demonstrate the surprisingly high efficacy ofExample III-A, III-B, and III-C of the present invention (particles ofPVP-peroxide embedded in hydrophobic wax delivery carrier) even at verylow levels of % bleaching agent—this may be especially suitable forpeople with sensitive teeth, or in geographies that have very stringentlimits on % peroxide. These results clearly demonstrate the surprisinglylarge impact of solid hydrophilic particles comprising bleaching agentembedded in hydrophobic wax delivery carrier of the present invention onefficacy.

The bleaching efficacy of Example II-E (with electromagnetic radiation)and Example VII-A (with electro-magnetic radiation) measured accordingto the ex-vivo procedure specified herein are listed in Table 3.

TABLE 3 Bleaching Efficacy Example II-E Example VII-A % H₂O₂ 3.07 2.95Description Solid particles of Solid particles of PVP-peroxide Sodiumpercarbonate embedded in a solid embedded in a solid wax deliverycarrier wax delivery carrier Particel >40 15 solubility in water (partsper 100 parts of water) Average reduction in 3.8 2.4 yellowness (−Δb*after one treatment)

TABLE 3 shows that Example II-E delivered 58% larger reduction inyellowness (−Δb*) compared to Example VII-A (3.8 Vs. 2.4) even thoughboth articles had the same level of % bleaching agent (about 3%).Specifically, these results clearly demonstrate the surprisingly highefficacy of an article (Example II-E) made with solid hydrophilicparticles (PVP-peroxide) that has a solubility of more than 40 parts byweight in 100 parts by weight of water Vs. an article (Example VII-A)made with solid hydrophilic particles (sodium percarbonate) that has asolubility of only 15 parts by weight in 100 parts by weight of water,even though both compositions had the same level of H₂O₂ (about 3%).These results clearly demonstrate the surprisingly large impact of thesolubility of the solid hydrophilic particles on bleaching efficacy.

The bleaching efficacy of Example II-E (with electromagnetic radiation)and Example I-A (with electromagnetic radiation) measured according tothe ex-vivo procedure specified herein are listed in Table 4.

TABLE 4 Bleaching Efficacy Example II-E Example I-A % H₂O₂ 3.07 2.77Description Solid particles of Solid particles of PVP-peroxidePVP-peroxide embedded in a solid embedded in a solid wax deliverycarrier wax delivery carrier Average thickness of 0.51 0.39 hydrophobicdelivery carrier (mm) Average reduction in 3.8  2.9  yellowness (−Δb*after one treatment)

TABLE 4 shows that Example II-E delivered 31% larger reduction inyellowness (−ΔV) compared to Example I-A (3.8 Vs. 2.9) even though botharticles had the same level of % bleaching agent (about 3%).Specifically, these results clearly demonstrate the surprisingly highefficacy of an article (Example II-E) made with a hydrophobic deliverycarrier having an average thickness of 0.51 mm Vs. an article (ExampleI-A) made with a hydrophobic delivery carrier having an averagethickness of only 0.39 mm, even though both compositions had the samelevel of H₂O₂ (about 3%). These results clearly demonstrate thesurprisingly large impact of the average thickness of the hydrophobicdelivery carrier on bleaching efficacy.

Concentration of Bleaching Agent at the Surface

The concentration of bleaching agent at the first surface Vs. secondsurface of Examples II-A, II-B, II-C, and II-D (samples taken from allfour batches) measured according to the procedure specified herein arelisted in table 5.

TABLE 5 Concentration of bleaching agent at the surface Example II-A,II-B, II-C, Example II-A, II-B, II-C, and II-D (samples taken and II-D(samples taken from all four batches) from all four batches) Firstsurface of article Second surface of article Description Surface of thearticle Surface of the article that is intended to on the far side ofthe contact the surface of first surface the oral cavity to be treated(in these examples, this is also the surface of the article into whichthe hydrophilic particles were pressed) Concentration of 1304 82bleaching agent at the surface (micrograms/ cm2)

TABLE 5 shows that the concentration of bleaching agent at the firstsurface is greater than the concentration at the second surface (1304micrograms/cm2 Vs. 82 micrograms/cm2). These results also show that theratio of the concentration of bleaching agent at the first surfacedivided by the concentration of bleaching agent at the second surface isabout 16 which is above a ratio of 1. These results clearly demonstratethe surprising ability of articles made using principles of the presentinvention to deliver more bleaching agents to the surface where they areneeded most.

The concentration of bleaching agent at the first surface Vs. secondsurface of Examples VI-A and VI-B (samples taken from both batches)measured according to the procedure specified herein are listed in table6.

TABLE 6 Concentration of bleaching agent at the surface Example VI-A andVI-B Example VI-A and VI-B (samples taken from (samples taken from bothbatches) both batches) First surface of article Second surface ofarticle Description Surface of the article Surface of the article thatis intended to on the far side of the contact the surface of firstsurface the oral cavity to be treated (in these examples, this is alsothe surface of the article into which the hydrophilic particles werepressed) Concentration of 1457 43 bleaching agent at the surface(micrograms/ cm2)

TABLE 6 shows that the concentration of bleaching agent at the firstsurface is greater than the concentration at the second surface (1457micrograms/cm2 Vs. 43 micrograms/cm2). These results also show that theratio of the concentration of bleaching agent at the first surfacedivided by the concentration of bleaching agent at the second surface isabout 34 which is above a ratio of 1. These results clearly demonstratethe surprising ability of articles made using principles of the presentinvention to deliver more bleaching agents to the surface where they areneeded most.

The concentration of bleaching agent at the surface of Examples II-A,II-B, II-C, and II-D (samples taken from all four batches), and surfaceof Comparative Example I-A measured according to the procedure specifiedherein are listed in table 7.

TABLE 7 Concentration of bleaching agent at the surface Example II-A,II-B, Comparative II-C, and II-D Example I-A (samples taken from Crest3D all four batches) Whitestrips Description Articles as ComparativeExample disclosed herein comprising about comprising about 9.5% H2O2 3%H2O2 Concentration of 1304 670 bleaching agent at the surface of articlethat is intended to contact the surface of the oral cavity to be treated(micrograms/cm2)

TABLE 7 shows that Examples II-A, II-B, II-C and II-D have a higherconcentration of bleaching agent at the surface Vs. Comparative ExampleI-A (1304 micrograms/cm2 Vs. 670 micrograms/cm2), even though ExamplesII-A, II-B, II-C and II-D had less % bleaching agent (about 3% Vs. about9.5%). Specifically, these results show that Examples II-A, II-B, II-Cand II-D had a concentration of bleaching agent at the surface about 2×that of Comparative Example I-A, even though Examples II-A, II-B, II-Cand II-D had less than ⅓^(rd) the % bleaching agent of ComparativeExample I-A. These results clearly demonstrate the surprising ability ofarticles made using principles of the present invention to deliver morebleaching agents to the surface where they are needed most.

Number of Solid Particles a Surface

The number of solid particles at a first surface and second surface ofExample V-A counted according to the procedure specified herein arelisted in table 8.

TABLE 8 Number of particles at a surface Example V-A Example V-A Firstsurface Second surface of article of article Description Surface of thearticle Surface of the article that is intended to on the far side ofthe contact the surface of first surface the oral cavity to be treated(in this example, this is also the surface of the article into which thehydrophilic particles were pressed) Average number of 24.6 1 solidparticles per cm2 at the surface

Table 8 shows that the number of solid particles per cm2 at the firstsurface of Example V-A is greater than the number of solid particles percm2 at the second surface (24.6 Vs. 1 per cm2). These data show that theratio of the number of particles per cm2 at the first surface divided bythe number of particles per cm2 at the second surface of Example V-A isabout 24.6, which is above a ratio of 1.

Ex-Vivo Procedure to Measure Bleaching Efficacy

-   -   1. Cut a circular disc (7.2 mm to 7.8 mm diameter×1.2 mm to 1.3        mm thickness) out of the front surface of a human incisor tooth.        Leave the facial surface intact and flatten the lingual surface        that has been cut out of the tooth. Store the tooth-disc in 15        to 20 ml of water that meets USP specification in a glass vial        for at least eighteen hours. Repeat this for a total of 12        teeth.    -   2. Measure the baseline L* and b* of the facial surface of each        tooth-disc individually placed on a standard white background        (White reference card used for digital & film photography, for        example DGK-XL X000B1R417 from DGK Color Tools) using a        hand-held spectrophotometer Konica Minolta 700d. The Konica        Minolta 700d spectrophotometer is used with an aperture of about        6.3 mm diameter, the observer angle is set at 2 degrees, the        illuminant is set at daylight color temperature of 5003K, and        specular reflection is excluded. To control the moisture level        in the tooth-disc during these measurements, a circular disc of        about 19 mm diameter is cut from a clear flexible polyethylene        film from about 0.01 mm to about 0.02 mm thick and placed over        the tooth-disc as soon as it is taken out of the water and the        L* and b* values are measured through this polyethylene-disc.        Take a set of three measurements per day on three separate days.        Store the tooth-disc in 15 to 20 ml of water that meets USP        specification in a glass vial for at least eighteen hours after        each set of three measurements. Calculate the average baseline        L* and b* for each tooth-disc across all three days.    -   3. Treat each tooth-disc individually with the composition to be        assessed. If the composition is a solid article, a) take the        tooth-disc out of the water and place the article on the facial        surface of the tooth-disc while it is still wet, and b) briefly        apply pressure to the article to simulate the article being        positioned on the teeth. If the composition is a semisolid        gel, a) take the tooth-disc out of the water and sandwich about        0.04 gram to about 0.05 gram of the gel between the tooth-disc        and a polyethylene-disc (about 19 mm in diameter cut from a        clear flexible polyethylene film from about 0.01 mm to about        0.02 mm thick), and b) briefly apply pressure to the        polyethylene-disc to simulate the gel being applied to the        teeth. Place this sandwich of tooth-disc+article or        tooth-disc+gel+polyethylene-disc in an oven at about 34 C (to        simulate the conditions of the facial surface of maxillary        anterior teeth) for about 60 minutes.    -   4. If the composition is used with electromagnetic radiation:    -   After 50 minutes of treatment with the composition, the        electromagnetic radiation is applied toward the facial surface        of the tooth-disc for 10 minutes.    -   The electromagnetic radiation is directed toward the facial        surface of the tooth-disc through the article or through the        gel+polyethylene-disc.    -   The electromagnetic radiation is delivered via a fiber-optic        cable (model number M71L01 from Thorlabs, Newton, N.J., USA)        connected to a high power LED with a peak intensity wavelength        of 455 nm (model number M455F1 from Thorlabs, Newton, N.J.,        USA). The LED is run at 1000 mA using an LED Driver (model        number DC2100, or DC4104 paired with DC4100-HUB from Thorlabs,        Newton, N.J., USA). The exit end of the fiber-optic cable is        mounted to help position the electromagnetic radiation        reproducibly against the outer surface of the strip. The exit        end of the fiber-optic cable is about 7 mm away from the tooth        surface. The intensity of the electromagnetic radiation from 400        nm to 500 nm measured at the central axis of the cone of        electromagnetic radiation at this distance needs to be from        about 175 mW/cm² to about 225 mW/cm² as measured by the method        disclosed herein.    -   This radiation is applied for about 10 minutes per tooth-disc.    -   5. Once 60 minutes of the treatment with the composition is        completed, the residual composition is removed from the        tooth-disc using a paper-towel and water.    -   6. After each treatment, store the tooth-disc in 15 to 20 ml of        water that meets USP specification in a glass vial for at least        eighteen hours.    -   7. Eighteen (or more) hours after the final treatment, measure        the post-treatment b* of each tooth-disc individually using the        procedure specified previously for the tooth-discs. This is done        on three subsequent days and averaged across all three days for        each tooth-disc.    -   8. For each tooth-disc, calculate the change in b* (yellow-blue        balance) as Δb*=b*_(post-treatment)−b*_(baseline) where a        negative change indicates the tooth-disc has become less yellow.        −Δb* is used as the primary measure of bleaching efficacy.        Calculate the average reduction in yellowness (−Δb*) across all        tooth-discs.        Procedure to Measure the Concentration of Bleaching Agent at a        Surface of a Hydrophobiic Delivery Carrier Comprising Bleaching        Agent (i.e. The Article)

The concentration of bleaching agent at the surface of a hydrophobicdelivery carrier comprising bleaching agent (i.e. the article) ismeasured according to the following procedure.

-   -   1. Cut a disc about 19 mm in diameter out of the article and        record its weight.    -   2. Weigh 0.425 g+/−0.003 g of water to a small plastic weigh        boat.    -   3. With a pair of tweezers place the disc on the water with the        surface to be tested in contact with the water. Make sure the        water reaches the perimeter of the disc but does not flow over        on top of the disc.    -   4. After 2 minutes, remove the disc and hold it vertically to        drip back into the weigh boat for 5 seconds.    -   5. Assay the water for % bleaching agent.    -   6. Calculate the total micrograms of bleaching agent in the        water based on the original amount of water added (0.425 g); and        divide this by the surface area of the disc contacted with the        water in cm2. This value (in micrograms/cm2) is the        concentration of bleaching agent at the surface of the disc        tested.    -   7. Perform steps 1 to 6 on a total of 24 discs and average all        24 values. This average value (in micrograms/cm2) is the        concentration of bleaching agent of the article at the surface        tested.

To validate the above procedure, the concentration of hydrogen peroxideat the first surface (gel-surface) of Comparative Example I-A must bemeasured and demonstrated to be from 550 micrograms/cm2 to 800micrograms/cm2.

Procedure to Count the Number of Particles at a Surface of a HydrophobicDelivery Carrier Comprising Bleaching Agent (i.e. The Article)

The number of particles at a surface of a hydrophobic delivery carriercomprising bleaching agent (i.e. the article) is measured according tothe following procedure.

-   -   1. Cut 24 squares of 1 cm×1 cm each from the article    -   2. Count the number of particles at the surface using a        microscope in each square.    -   3. Average the number particles counted at the surface across        all 24 squares. This is the number of particles/cm2 at that        surface.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An oral care article comprising: a) a solidhydrophobic delivery carrier in form of a strip having a length and awidth forming a first surface and having a thickness extending from thefirst surface to a second surface, wherein an average thickness of thestrip is less than about 3 mm; and b) solid hydrophilic particlescomprising a bleaching agent, wherein the solid hydrophilic particlesrelease the bleaching agent upon contact with water, wherein the solidhydrophilic particles are disposed in and embedded in the solidhydrophobic delivery carrier, wherein the solid hydrophilic particlesare disposed i) at least partially below the first surface, and ii) atleast partially at or above the first surface of the solid hydrophobicdelivery carrier; wherein at least about 20 parts by weight of the solidhydrophilic particles dissolve in about 100 parts by weight of waterand/or the solid hydrophilic particles increase in volume and/or weightby at least about 50% upon contact with water.
 2. The oral care articleof claim 1, wherein more than about 50% of the volume of the solidhydrophilic particles is disposed below or at the first surface of thehydrophobic delivery carrier.
 3. The oral care article of claim 1,wherein more than about 10% of a surface area of the solid hydrophilicparticles is disposed at the first surface of the hydrophobic deliverycarrier and exposed to an external environment surrounding thehydrophobic delivery carrier.
 4. The oral care article of claim 1,wherein a number-average equivalent-diameter or a volume-averageequivalent-diameter of the solid hydrophilic particles is in a range offrom about 1 micron to about 1000 microns.
 5. The oral care article ofclaim 1, wherein a ratio of the average thickness of the hydrophobicdelivery carrier and/or the article divided by a number-averageequivalent-diameter or a volume-average equivalent-diameter of the solidhydrophilic particles is from about 0.01 to about
 100. 6. The oral carearticle of claim 1, wherein the average thickness of the hydrophobicdelivery carrier or article is in a range of from about 0.01 mm to about3 mm.
 7. The oral care article of claim 1, wherein an average length ofthe hydrophobic delivery carrier is in a range of from about 35 mm toabout 100 mm.
 8. The oral care article of claim 1, wherein an averagewidth of the hydrophobic delivery carrier is in a range of from about 3mm to about 30 mm.
 9. The oral care article of claim 1, wherein thehydrophobic delivery carrier is shaped in a form of a dental arch. 10.The oral care article of claim 1, wherein the article is a unit-dosearticle and/or a removable article.
 11. The oral care article of claim1, wherein the article and/or the hydrophobic delivery carrier is asingle layer.
 12. The oral care article of claim 1, wherein aconcentration of the bleaching agent at the first surface is greaterthan a concentration of the bleaching agent at the second surface. 13.The oral care article of claim 12, wherein the concentration of thebleaching agent at the first surface is from about 1 microgram/cm² toabout 10000 micrograms/cm².
 14. The oral care article of claim 12,wherein the concentration of the bleaching agent at the first surface isfrom about 10 micrograms/cm² to about 5000 micrograms/cm².
 15. The oralcare article of claim 1, wherein the concentration of the bleachingagent at the second surface is from about 0.001 micrograms/cm² to about500 micrograms/cm².
 16. The oral care article of claim 1, wherein aratio of the concentration of the bleaching agent at the first surfacedivided by the concentration of the bleaching agent at the secondsurface is greater than
 1. 17. The oral care article according to claim1, wherein an overall concentration of bleaching agent is from about0.01% to about 10%, by weight of the article.
 18. The oral care articleaccording to claim 1, wherein an overall concentration of bleachingagent is from about 0.1% to about 3%, by weight of the article.
 19. Theoral care article of claim 1, wherein the solid hydrophilic particlescomprise from about 10% to about 50%, by weight of the solid hydrophilicparticles, of bleaching agent.
 20. The oral care article of claim 1,wherein the bleaching agent comprises peroxide.
 21. The oral carearticle of claim 20, wherein the bleaching agent comprises: (i) acomplex of hydrogen peroxide and polyvinylpyrrolidone (PVP) polymer,(ii) urea peroxide, or (iii) combinations thereof.
 22. The oral carearticle of claim 1, wherein the hydrophobic delivery carrier comprises amaterial having: (i) a needle consistency value of from about 0.1 toabout 100 as measured by ASTM D1321-16a; and/or (ii) a cone penetrationconsistency value of less than about 10 as measured by ASTM D937-07;and/or (iii) a drop melting point of from about 60° C. to about 120° C.as measured by ASTM D127-08; and/or (iv) a flexural stiffness of greaterthan about 50 g/cm as measured by ASTM D2923-95.
 23. The oral carearticle of claim 22, wherein the hydrophobic delivery carrier comprisesa material having: (i) a needle consistency value of from about 1 toabout 10 as measured by ASTM D1321-16a; and/or (ii) a cone penetrationconsistency value of less than about 5 as measured by ASTM D937-07;and/or (iii) a drop melting point of from about 80° C. to about 100° C.as measured by ASTM D127-08; and/or (iv) a flexural stiffness of fromabout 200 g/cm to about 500 g/cm as measured by ASTM D2923-95.
 24. Theoral care article of claim 1, wherein the hydrophobic delivery carriercomprises a wax, a polymer, or a combination thereof.
 25. The oral carearticle of claim 1, wherein the hydrophobic delivery carrier comprisesmicrocrystalline wax and/or polyethylene polymer.
 26. A kit comprisingthe oral care article of claim 1 and an electromagnetic radiation sourcecapable of directing electromagnetic radiation with one or morewavelengths in the range of from about 200 nm to about 1700 nm towardsat least one tooth, wherein the electromagnetic radiation impinges onthe outer surface of the hydrophobic delivery carrier in the range offrom about 175 mW/cm² to about 225 mW/cm².
 27. A method for whiteningteeth comprising the steps of: a) applying the oral care article ofclaim 1 to at least one tooth surface such that the first surface of thearticle contacts the at least one tooth surface; b) letting the articlestay on the at least one tooth surface for at least 1 minute; and c)optionally applying electromagnetic radiation for at least 1 minute.